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%\centerline{\big ANNUAL REPORT \hskip .2in 2000$-$AUGUST 2001}
%\vskip .2in
%\centerline{\big Canadian Institute for Theoretical Astrophysics}
%\vskip .1in
%\centerline{\big Institut d'Astrophysique Th\'eorique Canadien}
%\vskip .1in
%\centerline{\med 60 St. George St., Toronto, Ontario M5S 3H8}

\department{\big ANNUAL REPORT\hskip .3in
            2000$-$2001\break\vskip .05in
            Canadian Institute for Theoretical Astrophysics\break
            Institut d'Astrophysique Th\'eorique Canadien}
\institution{}
\location{}

\rptauthor{Jason Fiege} 
\rptauthor{Andrei Frolov} 
\rptauthor{Chris Matzner} 
\rptauthor{Christopher Thompson}

\maketitle

The following is an abbreviated version of the 2001 CITA Annual Report,
which covers scientific activities from September 2000 to August 2001.
The full report is available on the web at\hfil\break
\hbox{\tt http://www.cita.utoronto.ca/\~{}fiege/AnnRep}.

%\input{foreword_00.tex}
\section{\normalsize \bf FOREWORD}
 
The Canadian Institute for Theoretical Astrophysics is a nationally
supported research center for studies in theoretical astronomy and
related subjects, hosted by the University of Toronto, and receiving
research support from an NSERC collaborative special project grant, as
well as the Canadian Institute for Advanced Research.  CITA's primary
missions are to foster interaction within the Canadian theoretical
astrophysics community and to serve as an international center of
excellence for theoretical studies in astrophysics.  This report has
been prepared by Jason Fiege, Andrei Frolov, Christopher Matzner, and
Christopher Thompson.

Research at CITA covers a broad range of fields in astrophysical
theory.  During the 2000/2001 academic year the areas of study included: 

\par\hangindent=10pt\hangafter=1 $\bullet$~ cosmology:
microwave background anisotropies, large-scale structure, reionization, 
gravitational lensing, galaxy formation, Lyman alpha clouds;

\par\hangindent=10pt\hangafter=1 $\bullet$~ early universe: inflation, 
big bang nucleosynthesis, extra dimensions;

\par\hangindent=10pt\hangafter=1
$\bullet$~ dynamics: extra-solar planets, chaos, planet migration, 
galaxy clustering, warps, bars, and mergers;

\par\hangindent=10pt\hangafter=1 $\bullet$~ interstellar medium: 
Galactic HI distribution, molecular clouds, star-forming regions, dust physics;

\par\hangindent=10pt\hangafter=1 $\bullet$~ high energy astrophysics
and stellar physics:  accretion flows, AGN winds, supernovae, 
stellar pulsations, gamma-ray bursts, magnetars, stellar winds, AGB stars;

\par\hangindent=10pt\hangafter=1 $\bullet$~ 
general relativity: 
black holes, relativistic MHD, modifications of general relativity;

\par\hangindent=10pt\hangafter=1 $\bullet$~ 
computational physics: cosmological n-body simulations and hydrodynamics, 
particle-mesh and tree-code algorithms, internal modes of rotating stars;

%\input{personnel_00.tex}
\section{\normalsize \bf PERSONNEL}

The research staff of CITA for the 2000/2001 academic year (July 2000
to July 2001) is listed below.

\leftline{}\noindent
{\bf Faculty:}

\noindent $\bullet$ J. Richard Bond, Professor and Director\hfil\break
(Ph.D. Caltech 1979)

\noindent $\bullet$
Norman Murray, Professor and Associate Director \hfil\break
(Ph.D. Berkeley 1986)

\noindent $\bullet$
     Lev Kofman, Professor (Ph.D. Tartu 1985) 

\noindent $\bullet$
     Peter Martin, Professor (Ph.D. Cambridge 1972) 

\noindent $\bullet$
     Ue-Li Pen, Assistant Professor (Ph.D. Princeton 1995) 

\noindent $\bullet$
   Christopher Thompson, Associate Professor \hfil\break
(Ph.D. Princeton 1988) 

\leftline{}\noindent
{\bf Senior Research Associates:}

\noindent $\bullet$ 
     Dmitri Pogosyan, Ph.D. Tartu (1990) 

 \noindent $\bullet$ 
    Istvan Szapudi, Ph.D. Johns Hopkins (1995) 

 \noindent $\bullet$ 
    Ludovic Van Waerbeke, Ph.D. Toulouse (1997) 


\leftline{}\noindent
{\bf Research Associates:} 

 \noindent $\bullet$
    Phillip Arras, Ph.D. Cornell (2000) 

 \noindent $\bullet$ 
    Rennan Barkana, Ph.D. MIT (1997) 

\noindent $\bullet$ 
     Carlo Contaldi, Ph.D. Imperial College (2000) 

\noindent $\bullet$ 
     John Dubinski, Ph.D. Toronto (1991) 

\noindent $\bullet$
     Jason Fiege, Ph.D. McMaster (1999) 

\noindent $\bullet$ 
     Andrei Frolov, Ph.D. Alberta (2000) 

\noindent $\bullet$ 
     Henk Hoekstra, Ph.D. Groningen (2000) 

\noindent $\bullet$ 
     Robin Humble, Ph.D. Monash (1999) 

\noindent $\bullet$ 
     Christopher Matzner, Ph.D. UC Berkeley (1999) 

\noindent $\bullet$ 
     Mikhail Medvedev, Ph.D. UC San Diego (1997) 

 \noindent $\bullet$ 
    Simon Prunet, Ph.D. IAS Orsay (1998) 

\noindent $\bullet$ 
     Nir Shaviv, Ph.D. Israel Inst. Technology (1996) 

 \noindent $\bullet$ 
    Peter Van Hoof, Ph.D. Groningen (1997) 

\noindent $\bullet$ 
     Joseph Weingartner, Ph.D. Princeton (1999) 

\noindent $\bullet$ 
     Yanqin Wu, Ph.D. Caltech (1997) 


\leftline{}\noindent
{\bf Staff:} 

 \noindent $\bullet$ 
    Margaret Fukunaga, Administrator 

 \noindent $\bullet$ 
    Chris Loken, CITA Computing Manager 

 \noindent $\bullet$ 
    Laura Waters, Administrative Assistant 

\leftline{}\noindent
{\bf Students:}  Masters students working with CITA faculty were
K. Blagrave (Astronomy, completed Sept 2000; advisor Martin),
L. Chamandy (Astronomy; advisor Thompson), and 
T. Rothwell (Astronomy; advisor Martin).  Students working on Ph.D.
theses were K. Balgrave (Astronony; advisor Martin), 
A. Dirks (Astronomy; advisor Bond), G. Felder (Ph.D. 2001, Physics, 
Standford University; advisor Kofman), J. Karr (Astronomy; advisor Martin), 
R. McNaughton (Astronomy; advisor Murray), M. Ruetalo (Astronomy; advisor 
Bond); H. Trac (Astronomy; advisor Pen), P. Troischt (Physics and Astronomy, 
UNC; advisor Thompson), and P. Zhang (Astronomy; advisor Pen).
CITA also hosted several predoctoral fellows from outside institutions,
who included Y. Dolivet (Ecole Normale Superieur; advisor Kofman), K. Kadota 
(Berkeley; advisor Kofman), A. Karakas (Monash; advisor Humble),  
J. Kim (Seoul; advisor Dubinski), J. Martin (Jena University; advisor Kofman),
and T. Montroy (UCSB; advisor Bond).  Last but not least, CITA maintains 
a vigorous summer research program for Canadian undergraduate student
students.  The students are supported both by NSERC awards and by
faculty grants.  The students working at CITA in the summer of 2001 were
C. Armitage (UBC; advisor Bond), M. Bichan (Toronto; advisor Pen),
L. Chamandy (Queens; advisor Thompson); L. Leung (Toronto;
advisor Thompson), A. Mariampillai (Queens; advisor C. Matzner and C. Murray),
M. Pritchard (Toronto; advisor Dubinski), S. Tonnesen (Swathmore, working
with Bond, Contaldi, Pogosyan and Prunet); and B. Wang (UBC; advisor
Pen).

\leftline{}\noindent
{\bf Changes in 2000/2001:}
This was a bumper year for CITA post-docs, as five people moved on to faculty positions. Dmitri Pogosyan was hired by the
University of Alberta as an associate professor. Istvan Szapudi began an assistant professorship at the University of Hawaii in January
2001. Ludo van Waerbeke began a permanent research position at the Institut d'Astrophysique (Paris) in October 2000, and was soon
followed by Simon Prunet, who was hired by the IAP later in the year. (Van Waerbeke continued to divide his time between Paris and
Toronto during the 2000-2001 academic year.) Nir Shaviv and Rennan Barkana both accepted tenure track faculty positions in Israel, at
Hebrew University and the University of Tel Aviv, respectively, beginning in fall 2001. To add icing to the cake, we received news that
former CITA postdocs accepted permanent positions: Brad Hansen is joining the faculty of UCLA, James Murray is a Lecturer at
Leicester, Roman Scoccimarro joined New York University, Phil Armitage is joining the faculty at the University of Colorado from St.
Andrew's University, Brett Gladman joined the faculty at UBC, Andrew Jaffe became a Lecturer at Imperial College, Lloyd Knox joined UC
Davis Jan 2001, and Derek Richardson joined the faculty at the University of Maryland. 

Chris Thompson returned to CITA as an associate professor, having spent the last four years at the University of North Carolina at
Chapel Hill. Chris Matzner was promoted to a five-year Senior Research Associateship. New CITA post-docs in the fall of 2000 were
Rennan Barkana (who arrived from the Institute for Advanced Study, Princeton); Carlo Contaldi (who had just received his Ph.D. at
Imperial College London); Andrei Frolov (a new graduate of the University of Alberta); Henk Hoekstra (from the University of Groningen);
and Mikhail Medvedev (who had completed a post-doctoral position at Harvard University). New additions to CITA in the fall of 2001 will
include Andrei Beloborodov (arriving as a Senior Research Associate from Stockholm Observatory), and Gary Felder and Nicole
Lloyd-Ronning (both of whom received their PhDs from Stanford University in 2001). 

CITA faculty received a number of distinctions during the 2000-2001 year. Director Dick Bond was appointed a University Professor of the
University of Toronto. He was also elected to the Royal Society of London and became a Fellow of the Institute of Physics (U.K.). CITA
faculty Ue-Li Pen and Chris Thompson both received Premier's Research Excellence Award from the Province of Ontario, each carrying
with it a total of \$150,000 in funding. (That completes a clean sweep of the PREAs by recent additions to the CITA faculty: Lev Kofman was
awarded a PREA in 1997, and Norm Murray in 1999.) 



%\input{visitors_00matzner.tex}
\section{\normalsize \bf CITA VISITORS}

CITA has a vigorous visitors program bringing a number of 
Astronomy and Physics faculty members from other Canadian 
universities and from abroad for both extended stays and shorter 
visits.  The following is a list of all CITA visitors for the 
2000/2001 academic year.


\leftline{}\noindent
{\bf Long term visitors:}

\par\hangindent=10pt\hangafter=1 $\bullet$~ Omer Blaes - U.C. Santa Barbara 
\par\hangindent=10pt\hangafter=1 $\bullet$~      Arnold Boothroyd - Caltech 
 \par\hangindent=10pt\hangafter=1 $\bullet$~     Kenji Kadota - U.C. Berkeley 
\par\hangindent=10pt\hangafter=1 $\bullet$~      Sebastion Pichler - Ludwig Maximilians Universitat M\"unchen 
\par\hangindent=10pt\hangafter=1 $\bullet$~      Yacine Dolivet - L'ecole Normale Superieure (Paris) 
\par\hangindent=10pt\hangafter=1 $\bullet$~      Martin van Kerkwijk - Universiteit Utrecht 
\par\hangindent=10pt\hangafter=1 $\bullet$~      Margot Mandy - University of Northern B.C.
\par\hangindent=10pt\hangafter=1 $\bullet$~      Shinji Mukoyama - University of Victoria 
\par\hangindent=10pt\hangafter=1 $\bullet$~      Aristotle Socrates - U.C.
Santa Barbara 
\par\hangindent=10pt\hangafter=1 $\bullet$~      Tak-Pong Woo - National Taiwan University 
\par\hangindent=10pt\hangafter=1 $\bullet$~      Jun-Mein Wu - National Taiwan University 

\leftline{}\noindent
{\bf CITA senior visiting fellows:}

\par\hangindent=10pt\hangafter=1 $\bullet$~      Sun Kwok, Calgary 
\par\hangindent=10pt\hangafter=1 $\bullet$~      Norbert Bartel, York 

\leftline{}\noindent
{\bf Short term visitors:}

\par\hangindent=10pt\hangafter=1 $\bullet$~      F. Adams - University of Michigan 
\par\hangindent=10pt\hangafter=1 $\bullet$~      R. Allahverdi - University of Alberta 
\par\hangindent=10pt\hangafter=1 $\bullet$~      N. Arav - U.C. Davis 
\par\hangindent=10pt\hangafter=1 $\bullet$~      A. Atoyan - McGill University 
\par\hangindent=10pt\hangafter=1 $\bullet$~      D. Ballantyne - IOA, Cambridge 
\par\hangindent=10pt\hangafter=1 $\bullet$~      N. Bartel - York University 
\par\hangindent=10pt\hangafter=1 $\bullet$~      S. Bashinsky - MIT 
\par\hangindent=10pt\hangafter=1 $\bullet$~      S. Basu - University of Western Ontario 
\par\hangindent=10pt\hangafter=1 $\bullet$~      A. Beloborodov - Stockholm Observatory 
\par\hangindent=10pt\hangafter=1 $\bullet$~      F. Bernardeau - Saclay 
\par\hangindent=10pt\hangafter=1 $\bullet$~      E. Berschinger - MIT 
\par\hangindent=10pt\hangafter=1 $\bullet$~      L. Binette - Instituto de Astronomia 
\par\hangindent=10pt\hangafter=1 $\bullet$~      E. Blackman - California Institute of Technology 
\par\hangindent=10pt\hangafter=1 $\bullet$~      C. Borys - University of British Columbia 
\par\hangindent=10pt\hangafter=1 $\bullet$~      R. Bousso - U.C. Santa Barbara 
\par\hangindent=10pt\hangafter=1 $\bullet$~      B. Carr - Queen Mary College, London 
\par\hangindent=10pt\hangafter=1 $\bullet$~      J. Cartwright - California Institute of Technology 
\par\hangindent=10pt\hangafter=1 $\bullet$~      B. Chaboyer - Dartmouth University 
\par\hangindent=10pt\hangafter=1 $\bullet$~      D. Charbonneau - CfA, Harvard 
\par\hangindent=10pt\hangafter=1 $\bullet$~      M. Chen - SNO, Queen's University 
\par\hangindent=10pt\hangafter=1 $\bullet$~      M. Choptuik - University of British Columbia 
\par\hangindent=10pt\hangafter=1 $\bullet$~      P. Cottrell - Canterbury University, New Zealand 
 \par\hangindent=10pt\hangafter=1 $\bullet$~     H. Couchman - McMaster University 
\par\hangindent=10pt\hangafter=1 $\bullet$~      R. Crittenden - DAMTP, Cambridge 
 \par\hangindent=10pt\hangafter=1 $\bullet$~     A. Cumming - ITP, U.C. Santa Barbara 
\par\hangindent=10pt\hangafter=1 $\bullet$~      T. di Mateo - CfA, Harvard 
\par\hangindent=10pt\hangafter=1 $\bullet$~      S. Dodelson - Fermilab 
\par\hangindent=10pt\hangafter=1 $\bullet$~      L. Dones - Southwest Research Institute 
\par\hangindent=10pt\hangafter=1 $\bullet$~      M. Duncan - Queen's University 
\par\hangindent=10pt\hangafter=1 $\bullet$~      G. Efstathiou - IOA, Cambridge 
\par\hangindent=10pt\hangafter=1 $\bullet$~      G. Evrard - University of Michigan 
\par\hangindent=10pt\hangafter=1 $\bullet$~      G. Felder - Stanford 
 \par\hangindent=10pt\hangafter=1 $\bullet$~     G. Ferland - University of Kansas 
\par\hangindent=10pt\hangafter=1 $\bullet$~      M. Fich - University of Waterloo 
 \par\hangindent=10pt\hangafter=1 $\bullet$~     B. Fisher - U.C. Berkeley 
 \par\hangindent=10pt\hangafter=1 $\bullet$~     W. Freedman - Carnegie Observatories 
\par\hangindent=10pt\hangafter=1 $\bullet$~      V. Frolov - University of Alberta 
\par\hangindent=10pt\hangafter=1 $\bullet$~      T. Fukui - University of Waterloo 
\par\hangindent=10pt\hangafter=1 $\bullet$~      T. Fuller - University of Western Ontario 
\par\hangindent=10pt\hangafter=1 $\bullet$~      N. Gnedin - University of Colorado 
 \par\hangindent=10pt\hangafter=1 $\bullet$~     C. Gordon - University of Portsmouth 
\par\hangindent=10pt\hangafter=1 $\bullet$~      P. Goldreich - California Institute of Technology 
\par\hangindent=10pt\hangafter=1 $\bullet$~      A. Gruzinov - IAS, Princeton 
\par\hangindent=10pt\hangafter=1 $\bullet$~      Z. Haiman - Princeton 
\par\hangindent=10pt\hangafter=1 $\bullet$~      B. Hansen - Princeton 
\par\hangindent=10pt\hangafter=1 $\bullet$~      J. Heyl - California Institute of Technology 
\par\hangindent=10pt\hangafter=1 $\bullet$~      R. Henriksen - Queen's University 
\par\hangindent=10pt\hangafter=1 $\bullet$~      R. Hildebrand - University of Chicago 
\par\hangindent=10pt\hangafter=1 $\bullet$~      M. Holman - Harvard Smithsonian 
\par\hangindent=10pt\hangafter=1 $\bullet$~      M. Hudson - University of Waterloo 
\par\hangindent=10pt\hangafter=1 $\bullet$~      I.-G. Jiang - ASIAA 
\par\hangindent=10pt\hangafter=1 $\bullet$~      A. Karakas - Monash University\par\hangindent=10pt\hangafter=1 $\bullet$~      C. Keeton - University of Arizona 
\par\hangindent=10pt\hangafter=1 $\bullet$~      M. Kerscher - Johns Hopkins 
\par\hangindent=10pt\hangafter=1 $\bullet$~      S. Kenyon - Harvard 
\par\hangindent=10pt\hangafter=1 $\bullet$~      J. Kim - Seoul National University 
\par\hangindent=10pt\hangafter=1 $\bullet$~      A. Klypin - New Mexico State University 
 \par\hangindent=10pt\hangafter=1 $\bullet$~     R. Kolb - Fermilab 
 \par\hangindent=10pt\hangafter=1 $\bullet$~     D. Koranyi - CfA, Harvard 
\par\hangindent=10pt\hangafter=1 $\bullet$~      C. Kouveliotou - Marshall Space Flight Center 
\par\hangindent=10pt\hangafter=1 $\bullet$~      S. Kulkarni - California Institute of Technology 
\par\hangindent=10pt\hangafter=1 $\bullet$~      A. Kusenko - UCLA 
\par\hangindent=10pt\hangafter=1 $\bullet$~      S. Kwok - University of Calgary 
\par\hangindent=10pt\hangafter=1 $\bullet$~      D. Lai - Cornell University 
\par\hangindent=10pt\hangafter=1 $\bullet$~      G. Lake - University of Washington 
\par\hangindent=10pt\hangafter=1 $\bullet$~      K. Lake - Queen's University 
\par\hangindent=10pt\hangafter=1 $\bullet$~      R. Larson - Yale University 
\par\hangindent=10pt\hangafter=1 $\bullet$~      J. Lattanzio - Monash University 
\par\hangindent=10pt\hangafter=1 $\bullet$~      A. Lazarian - University of Wisconsin 
\par\hangindent=10pt\hangafter=1 $\bullet$~      Z.-Y. Li - University of Virginia 
\par\hangindent=10pt\hangafter=1 $\bullet$~      A. Liddle - University of Sussex 
\par\hangindent=10pt\hangafter=1 $\bullet$~      J. Lee - Academia Sinica 
\par\hangindent=10pt\hangafter=1 $\bullet$~      M.-H. Lee - U.C. Santa Barbara 
\par\hangindent=10pt\hangafter=1 $\bullet$~      J. Lesgourgues - SISSA, Trieste, Italy 
\par\hangindent=10pt\hangafter=1 $\bullet$~      Y. Levin - U.C. Berkeley 
\par\hangindent=10pt\hangafter=1 $\bullet$~      M. Lyutikov - McGill University 
\par\hangindent=10pt\hangafter=1 $\bullet$~      C.-P. Ma - University of Pennsylvania 
\par\hangindent=10pt\hangafter=1 $\bullet$~      J. Magueijo - Imperial College, London 
\par\hangindent=10pt\hangafter=1 $\bullet$~      J. Martin - University of Jena, Germany 
\par\hangindent=10pt\hangafter=1 $\bullet$~      S. Mashchenko - University of Montreal 
\par\hangindent=10pt\hangafter=1 $\bullet$~      B. Mason - California Institute of Technology 
\par\hangindent=10pt\hangafter=1 $\bullet$~      B. Matthews - McMaster University 
\par\hangindent=10pt\hangafter=1 $\bullet$~      A. Mazumdar - Imperial College 
 \par\hangindent=10pt\hangafter=1 $\bullet$~     A. McDonald - SNO, Queen's University 
\par\hangindent=10pt\hangafter=1 $\bullet$~      A. Melchiorri - Oxford University 
\par\hangindent=10pt\hangafter=1 $\bullet$~      Y. Mellier - Institute d'Astrophysique, Paris 
 
 
\par\hangindent=10pt\hangafter=1 $\bullet$~     K. Menou - Princeton University\par\hangindent=10pt\hangafter=1 $\bullet$~     L. Mersini - University of Pisa 
\par\hangindent=10pt\hangafter=1 $\bullet$~      C. Millar - University of Western Ontario 
\par\hangindent=10pt\hangafter=1 $\bullet$~      S. Mukohyama - University of Victoria 
\par\hangindent=10pt\hangafter=1 $\bullet$~      I. Murakami - National Institute for Fusion Science 
\par\hangindent=10pt\hangafter=1 $\bullet$~      J. Murray - University of Leicester 
\par\hangindent=10pt\hangafter=1 $\bullet$~      P. Myers - CfA, Harvard 
\par\hangindent=10pt\hangafter=1 $\bullet$~      R. Myers - McGill University 
\par\hangindent=10pt\hangafter=1 $\bullet$~      S. Myers - NRAO 
\par\hangindent=10pt\hangafter=1 $\bullet$~      J. Navarro - University of Victoria 
\par\hangindent=10pt\hangafter=1 $\bullet$~      F. Pearce - University of Durham 
\par\hangindent=10pt\hangafter=1 $\bullet$~      T.J. Pearson - California Institute of Technology 
\par\hangindent=10pt\hangafter=1 $\bullet$~      P.J.E. Peebles - Princeton University 
\par\hangindent=10pt\hangafter=1 $\bullet$~      S. Perlmutter - U.C. Berkeley 
\par\hangindent=10pt\hangafter=1 $\bullet$~      M. Pospelov - University of Minnesota 
\par\hangindent=10pt\hangafter=1 $\bullet$~      R. Pudritz - McMaster University 
\par\hangindent=10pt\hangafter=1 $\bullet$~      G. Starkman - Case Western University 
\par\hangindent=10pt\hangafter=1 $\bullet$~      E. Pierpaoli - University of British Columbia 
\par\hangindent=10pt\hangafter=1 $\bullet$~      J. Prochaska - U.C. Santa Cruz 
\par\hangindent=10pt\hangafter=1 $\bullet$~      E. Quataert - Princeton 
\par\hangindent=10pt\hangafter=1 $\bullet$~      P. Ricker - University of Chicago 
 \par\hangindent=10pt\hangafter=1 $\bullet$~     E. Rivera - Unvierstiy of Leuben, Belgium 
\par\hangindent=10pt\hangafter=1 $\bullet$~      A. Rosencweig - ThermaWave 
\par\hangindent=10pt\hangafter=1 $\bullet$~      J. Ruhl - U.C. Santa Barbara 
\par\hangindent=10pt\hangafter=1 $\bullet$~      B. Ryden - Ohio State University 
\par\hangindent=10pt\hangafter=1 $\bullet$~      V. Sahni - IUCAA, India 
\par\hangindent=10pt\hangafter=1 $\bullet$~      D. Sasselov - Harvard University 
\par\hangindent=10pt\hangafter=1 $\bullet$~      E. Scannapieco - U.C. Berkeley 
\par\hangindent=10pt\hangafter=1 $\bullet$~      R. Scoccimarro - IAS, Princeton 
\par\hangindent=10pt\hangafter=1 $\bullet$~      D. Scott - University of British Columbia 
\par\hangindent=10pt\hangafter=1 $\bullet$~      S. Seager - IAS, Princeton 
 \par\hangindent=10pt\hangafter=1 $\bullet$~     S. Shandarin - University of Kansas 
\par\hangindent=10pt\hangafter=1 $\bullet$~      J. Sievers - California Institute of Technology 
 \par\hangindent=10pt\hangafter=1 $\bullet$~     A. Smolyakov - University of Alberta 
\par\hangindent=10pt\hangafter=1 $\bullet$~      G. Starkman - Case Western Reserve University 
\par\hangindent=10pt\hangafter=1 $\bullet$~      P. Steinhardt - Princeton University 
\par\hangindent=10pt\hangafter=1 $\bullet$~      J. Stil - Queen's University 
\par\hangindent=10pt\hangafter=1 $\bullet$~      J. Stone - University of Maryland 
\par\hangindent=10pt\hangafter=1 $\bullet$~      T. Souradeep - Kansas State University 
\par\hangindent=10pt\hangafter=1 $\bullet$~      S. Talon - University of Montreal 
\par\hangindent=10pt\hangafter=1 $\bullet$~      R. Thacker - McMaster University 
\par\hangindent=10pt\hangafter=1 $\bullet$~      S. Tremaine - Princeton University 
\par\hangindent=10pt\hangafter=1 $\bullet$~      P. Troischt - University of North Carolina 
 \par\hangindent=10pt\hangafter=1 $\bullet$~     A. Tseytlin - Ohio State University 
 \par\hangindent=10pt\hangafter=1 $\bullet$~     B. Unruh - University of British Columbia 
\par\hangindent=10pt\hangafter=1 $\bullet$~      G. Ushomirsky - U.C. Berkeley 
 \par\hangindent=10pt\hangafter=1 $\bullet$~     A. Van Proeyen - University of Louvain, Belgium 
 \par\hangindent=10pt\hangafter=1 $\bullet$~     R. van de Weygaert - Kapteyn Institute 
\par\hangindent=10pt\hangafter=1 $\bullet$~      L. van Waerbeke - Institut d'Astrophysique, Paris 
\par\hangindent=10pt\hangafter=1 $\bullet$~      K. Verner - University of Kansas 
\par\hangindent=10pt\hangafter=1 $\bullet$~      M. Voit - Space Telescope Science Institute 
\par\hangindent=10pt\hangafter=1 $\bullet$~      S. Vogt - U.C. Santa Cruz 
\par\hangindent=10pt\hangafter=1 $\bullet$~      J. Wadsly, - McMaster University 
\par\hangindent=10pt\hangafter=1 $\bullet$~      D. Wands - University of Portsmouth 
\par\hangindent=10pt\hangafter=1 $\bullet$~      M. West - University of Hawaii at Hilo 
 \par\hangindent=10pt\hangafter=1 $\bullet$~     L. Widrow - Queen's University 
\par\hangindent=10pt\hangafter=1 $\bullet$~      G. Yepes - Universidad Autonoma de Madrid 

\vfil\eject
%\input{ciar_00.tex}
\section{\normalsize \bf CIAR AND CITA}

{\bf The Canadian Institute for Advanced Research} supports a number of programs
chosen for their high intellectual promise and
interdisciplinary character. The CIAR Cosmology and Gravity Program has
nodes at UBC (Fellows Bill Unruh and Matt Choptuik), at the
University of Alberta (Fellows Valery Frolov and Don Page), at the
University of Victoria (Fellow Werner Israel and Scholar Julio Navarro),
at McMaster University (Fellow Hugh Couchman), at Queen's University
(Scholar Mark Chen), at the University of Toronto (Fellows Ray
Carlberg, Scholars Barth Netterfield and Amanda Peet), at the Hertzberg
Institute 
(Fellow Simon Lilly), at the Perimeter Institute (Fellow Rob Myers)  
and at CITA, where Dick Bond and Lev Kofman are
CIAR Fellows and Ue-Li Pen is a CIAR scholar. There is
also a large distinguished network of CIAR Associates of this Program
around the world. The Program is in its third five year period and
Scott Tremaine is the Director. The academic interaction between CIAR
Fellows and other CITA visitors and researchers, and the
administrative cooperation between CITA and CIAR in attracting excellent
cosmologists, continues to make Toronto and Canada a lively
place for research in theoretical cosmology. The Program has recently been
renewed 
for a fourth five-year term. 

%\input{sackler_00.tex}
\section{\normalsize \bf SACKLER VISITING ASTROPHYSICIST}

CITA received a generous gift from the Raymond and Beverly Sackler
Foundation to endow the {\bf Raymond and Beverly Sackler Visiting
Astrophysicist Program}. Each year CITA invites an internationally
distinguished scholar conducting research in theoretical astrophysics
to give two lectures at the University of Toronto. The researcher also
meets informally with faculty and postdoctoral fellows at CITA as well
as researchers and students in the Department of Astronomy and other
departments. The visit is intended to be the highlight of the academic
year at CITA.

The fifth Sackler lecture, titled `How Does the Sun Shine?', was
delivered by Prof. John Bahcall of the Institute for Advanced Study
(Princeton) on 1 November 2001 to an enthusiastic audience of students
and faculty. Prof. Bahcall summarized his work, stretching back almost
40 years, on the production and detection of Solar neutrinos, as well
as the brilliant efforts of hundreds of experimental physicists across
the globe to detect these elusive particles. The longstanding mystery
of the missing Solar neutrinos recently found a dramatic solution in
the detection of neutrino oscillations by the Sudbury Neutrino
Observatory. The next day, John Bahcall delivered a second, more
technical, lecture on the properties of neutrinos as deduced from the
latest Solar neutrino experiments.

This year's Sackler Lectureship was combined with a visit by
Prof. Neta Bahcall of the Astronomy Department at Princeton
University. She has spearheaded efforts to measure fundamental
cosmological parameters through techniques such as the statistics of
high redshift galaxy clusters. On Nov 1, Prof. Bahcall gave a
comprehensive review of current measurements of the mass density,
cosmological curvature, and cosmological constant, based on a variety
of observational stategies, and demonstrated a remarkable convergence
in the results of these independent methods.

The previous {\bf Raymond and Beverly Sackler Visiting
Astrophysicists} have been: Sir Martin Rees of Cambridge (1997); Peter
Goldreich of Caltech (1998); Frank Shu of Berkeley (1999); and Jim
Peebles of Princeton (2000).

%\input{conferences_00.tex}
\section{\normalsize \bf CONFERENCES SUPPORTED BY CITA}

CITA supports scientific workshops and meetings in Canada on subjects of
interest to theoretical astrophysics.  Meetings supported by CITA in 1999/2000
were:

\par\hangindent=10pt\hangafter=1 $\bullet$~ Kingston 2000 Meeting: ``Directions in Theoretical Astrophysics at the Turn of the Millennium''
     26-30 August 2000, Fields Institute, Toronto
     Organizers: D. Bond, D. Henriksen, L. Kofman, N. Murray,
     U-L. Pen, L. Widrow 

\par\hangindent=10pt\hangafter=1 $\bullet$~ 
     ``Black Holes III: Theory and Mathematical Aspects"
     19-23 May 2001, Kananaskis, Alberta
     Organizers: D. Page, V. Frolov 


\par\hangindent=10pt\hangafter=1 $\bullet$~``Ninth Canadian Conference
     on General Relativity and Relativistic Astrophysics" 24-26 May
     2001, University of Alberta Organizers: H. Kunzle, S. Morsin,
     E. Woolgar

\par\hangindent=10pt\hangafter=1 $\bullet$~``CITA Workshop on High
     Performance Computational Astrophysics" 31 May - 1 June 2001,
     Toronto Organizers: U-L. Pen, J. Dubinski, H. Couchman,
     J. Wadsley, R. Humble

\par\hangindent=10pt\hangafter=1 $\bullet$~``White Dwarfs as Dark
     Matter" 19-22 August 2001, University of British Columbia
     Organizers: H. Richer, D. Scott


In addition, a collaboration between CITA, McMaster, Waterloo, and
Queen's University has produced an active Star Formation Group in the
Southern Ontario region which holds an annual Jamboree.  At CITA,
informal seminars also convene to discuss the physics of the early
universe, and theories and observations of gamma ray bursts.


%\input{facilities_00.tex}
\section{\normalsize \bf FACILITIES}


CITA occupies the 12th floor of the McLennan Physical Laboratories at
the downtown campus of the University of Toronto. The main-stay of
CITA's high-performance computing resources is a Compaq "Wildfire"
GS320 computer with 32 alpha processors and 64GB of RAM. This machine
is intended primarily for cosmological simulations, cosmological
hydrodynamics, simulations of galaxy formation, and CMB map
analysis. However, it is available to any CITA researcher whose
research depends on high performance parallel computing. This computer
was obtained with a "Canadian Fund for Innovations" (CFI) grant,
proposed by Peter Martin, Richard Bond, and Ray Carlberg, along with
the Atmospheric Physics group and the Chemistry department. CITA also
has two powerful Beowulf clusters. A dedicated 28 processor Intel
cluster with 8GB of RAM is funded by John Dubinski and used for his
research in galactic dynamics. A second Beowulf cluster with 1GB of
memory is funded by Peter Martin in collaboration with M. Duncan
(Queen's) and K. Innanen (York). This cluster is dedicated to
computationally intensive simulations in molecular and atomic physics,
as well as planetary dynamics. CITA also houses a large SCSI Raid
array with a storage capacity of 550GB. CITA researchers also have
access to several other multi-processor machines, including 4 Quad
Alpha ES40s each with four 500 MHz processors and 4 GB of RAM, and a
quad ES45 with 1 GHz processors. CITA also has two older
multi-processor machines, including an 8 processor SGI Origin 2000
system with 4GB of memory, and a 4 processor Compaq AlphaServer 2100
system with 1GB of memory. CITA is about to take delivery of 8 Dell
Quad Itanium servers with 512GB core memory. 

Every researcher at CITA has a desktop computer for general use and
smaller computational tasks. These are Intel and AMD-based personal
computers running Linux, although there are several Compaq Alpha
workstations, SGI Indigo workstations, SGI Personal IRISes, SUN
SPARCstations, and X terminals. All of these systems are networked
together, and used either individually or in parallel. All of these
systems are supported by a Sun Ultra 5 back-end file and network
server, with about 200 gigabytes of disk. CITA's network is fully
switched, with 10 and 100 megabit connections to offices (depending on
the computers present) and a 100 megabit link to the campus network
and the Internet. Researchers also have access to a number of
peripheral devices, including a high-quality colour laser printer, a
dye-sublimation colour printer, several inkjet colour printers, a
high-speed black-and-white laser printer capable of double-sided
printing, an optical scanner, and various tape drives (e.g., an 8TB
AIT-3 tape library).

%\input{council_00.tex}
\section{\normalsize \bf CITA COUNCIL}

CITA is both an Institute within the School of Graduate Studies of the
University of Toronto, and a non-profit corporation (CITA, Inc.).
Relations between the two CITAs are governed by a Letter of Agreement
between CITA~Inc.\ and the University of Toronto that was signed in
1989. The CITA Council consists of eight members, five selected from
the CITA~Inc.\ membership of over 50 researchers in co-operation with
the Canadian Astronomical Society (of which they must also be
members), and two {\it ex officio}: the Director of CITA and the Dean
of the School of Graduate Studies of the University of Toronto or his
designate. 
 
Members of CITA Council for the second half of 2000 were:

\noindent $\bullet$~ Richard Bond, CITA Director\hfil\break
\noindent $\bullet$~ Richard Henriksen, CITA Chair, Queen's University\hfil\break
\noindent $\bullet$~ Donald Cormack, S.G.S., University of Toronto\hfil\break
\noindent $\bullet$~ Hugh Couchman, McMaster University\hfil\break
\noindent $\bullet$~ Martin Duncan, Queen's University\hfil\break
\noindent $\bullet$~ David Hartwick, University of Victoria\hfil\break
\noindent $\bullet$~ Kim Innanen, York University


%\input{science_overview_baas_00.tex}
\section{SCIENTIFIC OVERVIEW 2001}

The research program at CITA encompasses all the major areas in
astronomy broken down in the main categories of cosmology, galaxies,
interstellar medium, stars and planets.  In this report, we review the
main activities at CITA during the 2000/2001 academic year.

\subsection{Cosmology}


{\bf Barkana}, Haiman (Princeton) and Ostriker (Princeton) studied the
constraints that high-redshift structure formation in the universe
places on warm dark matter (WDM) dominated cosmological models. In WDM
models, the dark matter particles are given random initial
velocities. This smooths the density distribution on small scales,
suppressing the densities and central concentrations of dwarf
galaxies. These effects improve the agreement between the cold dark
matter model and observations of the present universe. However, in WDM
models the numbers of galaxies are strongly altered at high
redshifts. The observed reionization of the universe, and the presence
of massive high-redshift quasars, both place strong constraints on WDM
models.

In light of recent observations of quasar spectra, {\bf Barkana} has studied
the observational signatures of different stages of the reionization
epoch. The central stage of reionization is the overlap stage, during
which the ionized-hydrogen bubbles produced by individual sources
overlap each other and reionize the low-density gas which takes up
most of the volume of the universe. Some neutral hydrogen remains in
dense clumps which are then slowly reionized during post-overlap.
{\bf Barkana} showed that the recent observations are consistent with the
post-overlap stage, and therefore further efforts are required for a
conclusive observation of the overlap stage.

{\bf Barkana} is developing detailed theoretical models of the various
stages of the reionization of the universe. One goal is to show which
physical parameters determine the character and the length of the
reionization era. He is exploring a number of scenarios for
reionization, depending on various possible ionizing source
populations.

{\bf Barkana} and Scannapieco (Berkeley) are developing an analytical
formalism appropriate for studying structure formation in
inhomogeneous environments. The standard derivation of the mass
distribution of dark matter halos depends on the statistics of the
density distribution in spheres of various sizes, all about a single
random point. The authors extend this to a two-point formalism, and
derive an approximate expression for the mass distribution of halos in
the neighborhood of an object with a fixed mass and formation
time. This formalism should be useful in many applications which
involve the feedback effects of galaxies on their surroundings.

Over the past two years, Cosmic Microwave Background (CMB) data from
the balloon-borne Boomerang and MAXIMA experiments and later from the
interferometric experiments DASI and the Cosmic Background Imager
(CBI) on sub-degree angular scales have revolutionized our knowledge
of the Universe. CITA continued its strong efforts on CMB analysis, as
members of the Boomerang and CBI teams, and determining their
cosmological implications.   The {\bf CITA Boomerang group}
 consists of Dick {\bf Bond}, Carlo {\bf Contaldi}, Dmitry
{\bf Pogosyan} and Simon {\bf Prunet}, along with Barth Netterfield of the
Astronomy Department. They have been intensively engaged in analyzing
the 10 days of Boomerang Long Duration Balloon flight data,
determining the significance of the features in the measured power
spectrum and deriving cosmological parameters from it. CITA hosted the
entire Boomerang team and many smaller focus groups during this
period.

The {\bf CITA Boomerang group} along with Hivon (Caltech) have constructed a
very fast method for the estimation of CMB angular power spectra. It
involves the simulation of an observation in a Monte Carlo procedure
to estimate the biasing terms in the measured power. The resulting
estimator was applied succesfully in the power spectrum estimation in
the latest BOOMERANG results. The method is currently one of the most
competitive methods for the fast estimation of CMB power
spectra. 

Similar ``FASTER'' ideas are being applied by the {\bf CITA group} to
estimation of non-Gaussian components in the Boomerang data, using
novel ways of estimating the reduced higher-point correlation
functions in multipole space. Two summer undergraduate students,
C. Armitage and S. Tonnesson, worked on this project as well.

The measured spectrum confirms the paradigm of adiabatic perturbations
as the source of the structure in the Universe and is in agreement
with the inflationary models of the early Universe which specify the
seeds for these perturbations. The CITA group derived values on the
main parameters governing the inflation-based adiabatic fluctuation
model. They found that the Universe is nearly spatially flat, has
baryon content in agreement with the predictions from the Big Bang
nucleosynthesis calculations, and strongly indicates that the bulk of
the energy in the Universe is dark, possibly in the form of vacuum
energy.

The {\bf CITA Boomerang group} and summer undergraduate student Kris
Sigurdsen used the Boomerang and other CMB data, in conjunction with
large scale structure and supernova data, to constrain the equation of
state of the dark energy, finding it is compatible with a cosmological
constant explanation, although rolling scalar fields are still a
viable option.

The analysis of the unique CBI interferometric dataset has required
the implementation of new analysis methods. A CITA group consisting of
Dick {\bf Bond}, Carlo {\bf Contaldi}, Ue-Li {\bf Pen}, Dmitry {\bf Pogosyan} and Simon {\bf Prunet}
in collaboration with the CBI team have carried out the first analysis
of mosaiced CMB interferometric fields of view. The results provide
measurements of the CMB power spectrum at angular scales above
$\ell=1000$ (the end of the Boomerang range) where very few
measurements have been carried out so far. The first round of results
is to be published in early 2002.

The huge worldwide investment in CMB experiments should make the
Sunyaev-Zeldovich (SZ) effect a key probe of the cosmic web in the
near future. For the promise to be realized, substantial development
of simulation and analysis tools to relate observation to theory is
needed. The high nonlinearity and dissipative/feedback gas physics
lead to highly non-Gaussian patterns that are much more difficult to
analyze than Gaussian primary anisotropies for which the procedures
are reasonably well developed. Historical forecasts for what CMB
experiments might see used semi-analytic tools, including large scale
map constructions, with localized and simplified pressure structures
distributed on a point process of (clustered) sources. Hydro studies
beyond individual cluster/supercluster systems were inadequate, but
now large-volume simulations with high resolution are beginning to
shift the balance.  {\bf Bond} and student Marcelo Ruetalo, in collaboration
with James Wadsley (McMaster) and Mike Gladders, have illustrated this
by applying ``Gasoline'' (parallelized Tree+SPH) computations to
construct SZ maps and derive statistical measures. They believe rapid
Monte Carlo simulations using parameterized templates centered on
point processes informed by optical and other means on the
observational side, and by hydro simulations on the theory side,
should play an important role in pipelines to analyze the new SZ field
data.  They show that localized sources should dominate upcoming SZ
experiments, identify sources in the maps under filtering and noise
levels expected for these experiments, use the RCS photometric optical
survey as an example of redshift localization, and discuss whether
cosmic web patterns such as superclusters can be enhanced when such
extra source information is supplied.


As an alternative to computing large-scale simulations of cosmic
structure formation in ever larger periodic boxes, {\bf Bond} and Wadsley
have designed a relatively small set of modest sample patches
constrained to have bulk physical properties which characterize the
main statistical variations from sample to sample. Statistical
quantities computed for each simulated patch are combined using Bayes
theorem, with this importance sampling ending when a required accuracy
is achieved.  They have found that patch-smoothed shear values,
spanning the range from void-like to overdense regions, are excellent
control parameters for the constrained bulk properties, defining
``shearing patches''. It is essential to ensure that the mass
resolution scale be small enough to capture the essential physics, and
that the patches be large enough to avoid extreme tidal distortion
over the redshift range of interest. Long wavelengths and tidal forces
must be properly included for each shearing patch simulated. An
advantage of this technique is that it can be naturally ``parallel by
shell''.  They have developed a fast and accurate TreePM-SPH code with
low memory cost which allow them to evolve shearing patches with
strong tides in single processors, with cross-talk only occurring at
the post-processing level of the statistical quantities of interest, a
radical compression of the patch information.  Long waves are
incorporated by optimally sampling k-space out to arbitratily large
scales, and simulating non-periodically with multiple particle masses
and linearly evolved external tides.  They demonstrate the technique
for the Lyman alpha forest, using a set of modest simulations
resolving the essential Jeans scale (0.1 Mpc).  The resulting dynamic
patches combine to match the observed Lyman alpha absorber column
density characteristics including the sharp change in $dn/dN_{HI}$
slope at HI column depth $10^{14}$. Exploring the Cosmic Web
structures producing the QSO absorption features we find a strong
association between columns above $10^{14.5}$ absorbers and dwarf
galaxies.


Carlo {\bf Contaldi} and Magueijo (Imperial) have developed a method for the
generation of simulated CMB with a Bispectrum decoupled from the power
spectrum.  (This method is a restriction of transformation based
simulation techniques.) The work involved the development and
implementation of a "Harmonic" probability distribution function, a
non-Gaussian PDF related to the well known Edgeworth Expansion around
a Gaussian but with better mathematical properties (positive
definiteness is ensured).

Henk {\bf Hoekstra}, Howard Yee (Toronto), and Mike Gladders (Toronto) used
the imaging data of the Red-Sequence Cluster Survey to measure the
weak lensing signal induced by large scale structure. To date, 24% of
the data have been analysed, and a significant lensing signal is
detected. In particular, in combination with other (deeper) surveys,
these measurements provide valuable constraints on cosmological
parameters.

Henk {\bf Hoekstra}, Yee, and Gladders used the RCS imaging data to obtain
the constraints on galaxy biasing from weak gravitational lensing. The
RCS data alone allow a measurement of the ratio of the bias parameter
and the galaxy-mass cross-correlation coefficient as a function of
scale. In collaboration with Ludo {\bf van Waerbeke} and Yannick Mellier, a
first attempt has been made to measure the bias parameter and the
cross correlation coefficient separately. These results provide a
unique, and important constraints on models of galaxy formation.

Henk {\bf Hoekstra}, Mike Gladders, Howard Yee, and Erica Ellingson obtained
follow-up observation of a z=0.78 cluster of galaxies which shows (for
this redshift) unprecedented strong lensing features. A detailed
modeling of the mass distribution and measured redshift for the arcs
allows one to constrain the density parameter of the universe through
a geometrical method: the location of the lensed features depend on
the angular diameter distances, which in turn depend on the cosmology.

Modification of the new Tree-PM cosmological N-body code (Kim,
{\bf Dubinski}, Park) is being carried out to add SPH fluid dynamics for
applications such as the Sunyaev-Zeldovich effect.

Mikhail {\bf Medvedev} and Ramesh Narayan (IAS \& Harvard) are attempting to
explain the deficit of large clouds of cold gas in cooling flows of
several galaxy clusters revealed by Chandra and XMM. Such clouds were
expected to rapidly drop out of the flow because of run-away
cooling. Preliminary theoretical results indicate that thermal
conduction is such weakly collisional systems may be as high as a
fraction of the Spitzer value, despite the presence of strong
turbulent magnetic fields. This should be enough to inhibit fast mass
drop-out.

Mikhail {\bf Medvedev} developed a phenomenological model of
self-interacting dark matter (SIDM) with quantum flavor mixing. He
showed that this model possess all attractive features of both a
conventional SIDM and an annihilating dark matter model, but does not
suffer from their severe problems. In this model, different mass
eigenstates of dark matter particles separate in the gravitational
field of a galaxy. Heavy states remain bound in the halo (and, thus,
form the halo) and light ones escape. As the density increases,
scattering of mass states off each other converts some of the heavy
states into the escaping light ones, which lowers the central density
and flattens the core.

Mikhail {\bf Medvedev} investigated the dynamics of flavor-mixed dark matter 
in the early universe. This consideration puts important constraints
on the parameters of the model, such as the masses of dark matter
particles. The allowed mass of the heavier mass-state is below a tenth
of a GeV in the non-degenerate case and is somewhat larger, around or
below a few GeV, in the most degenerate case.

In a series of papers, {\bf Pen} together with J. Lee (Tapei), U. Seljak
(Princeton), R. Crittenden (DAMTP), P. Natarajan (Yale), and T. Theuns
(Cambridge) have calculated the statistics of galaxies alignments from
linear theory, and compared the results with simulations and
observations. The effects are consistent across the three fronts, and
provide an estimate of the level of contamination for weak lensing
surveys. The alignments themselves can be used to reconstruct the
primordial gravitational shear field.

{\bf Pen} and Zhang (Toronto) used analytic hierarchical correlation models
to compute the two point statistics of the pressure fluctuations which
determine the Sunyaev-Zeldovich effect. It was demonstrated how the
redshift evolution of the SZ power spectrum can be deconvolved by the
appropriate cross correlation with galaxy surveys.

{\bf Pogosyan}, S. Colombi (IAP) and T. Souradeep (Kansas State) presented a
numerical study of topological descriptors of initially Gaussian and
scale-free density perturbations evolving via gravitational
instability in an expanding universe. Independent of the degree of non
linearity, the measured Euler number of the excursion set at the
percolation threshold is positive and nearly equal to the number of
isolated components, suggesting that these structures are trees. Their
study of critical point counts reconciles the clumpy appearance of the
density field at percolation level with measured filamentary local
curvature. In the Gaussian limit, they found the 3D field percolates
at threshold higher than 1sigma level, in contrast to widely held
belief that percolation happens at 1sigma.

Szapudi, {\bf Prunet}, {\bf Pogosyan}, {\bf Bond}, and Szalay (JHU) have proposed and
implemented a fast, universally applicable method for extracting the
angular power spectrum from CMB temperature maps by first estimating
the correlation function. Their procedure recovers the $C_l$'s using $N^2$
(but potentially $N \log N$), operations, where $N$ is the number of
pixels. This is in contrast with standard maximum likelihood
techniques which require $N^3$ operations. This method makes no special
assumptions about the map, unlike present fast techniques which rely
on symmetries of the underlying noise matrix, sky coverage, scanning
strategy, and geometry. This enables for the first time the analysis
of megapixel maps without symmetries. The key element of the technique
is the accurate multipole decomposition of the angular correlation
function. The $C_l$ error bars and cross-correlations are found by a
Monte-Carlo approach. This technique was applied to a large number of
simulated maps with Boomerang sky coverage, and it was shown that the
technique provides an unbiased estimator of the $C_l$'s. Even though the
method is approximate, the error bars obtained are nearly optimal, and
converged only after few tens of Monte-Carlo realizations. The
published paper also discussed generalizations of the technique to a
non-diagonal noise matrix, minimum variance weighting schemes,
polarization, and higher order statistics.

Szapudi, in collaboration with Moore (CMU), Connolly (UPitt) and
Nichol (CMU) present a new algorithm for the fast computation of
N-point correlation functions in large astronomical data sets. The
algorithm is based on kdtrees which are decorated with cached
sufficient statistics thus allowing for orders of magnitude speed-ups
over the naive non-tree-based implementation of correlation
functions. They further address the use of controlled approximations
within the computation which allows for further acceleration. In
summary, our algorithm now makes it possible to compute exact,
all-pairs, measurements of the 2, 3 and 4-point correlation functions
for cosmological data sets like the Sloan Digital Sky Survey and the
next generation of Cosmic Microwave Background experiments.

{\bf van Waerbeke}, Hamana (IAP), Scoccimarro (IAS), Colombi (IAP), and
Bernardeau (Saclay) have completed a study of the non-linear signal
expected in cosmic shear surveys generated by the non-linear
clustering of large scale structures. One aspect of this problem is
studied in CITA-2000-48, where they compute the skewness of the
convergence field using ray-tracing simulations (for different
cosmological models), compared to the semi-analytical predictions
based on an extension on the bi-spectrum in the non-linear regime
(Scoccimarro). The results agree remarkably well, showing that we are
already able to predict to a good accuracy ($10\%$) the level of
non-linearity in mass maps. Another aspect of the problem is the
measurement of the non-linear signal itself on real data: this is know
to be very difficult on reconstructed mass maps, because of the biases
generated during the mass reconstruction process. With Francis
Bernardeau and Yannick Mellier (IAP), {\bf van Waerbeke} is developing a new
estimator based on the shear 3-points function (which is directly
measured on the data). This function would naively vanish for symetry
reasons, and they are building an estimator which does not vanish but
is also optimal for signal extraction.

{\bf van Waerbeke} has continued a long-term project with Mellier (IAP),
Radovich (Naples), Bertin (IAP), Dantel-Fort (Obs Paris), and other to
measure the lensing effect by large scale structures. They obtained a
cosmic shear measurement on two data sets: one is the VIRMOS-Descart
lensing survey (16 deg$^2$ in four colors, still in progress), and
the other was obtained on the Very Large Telescope ANTU, and combined
0.64 deg$^{2}$ of data over 1000 deg$^2$ on the sky (astro-ph/0011251,
2001A\&A...368..766). They measured for the first time various
statistics simultaneously on the same data set: the shear top-hat
variance, the aperture mass and the shear correlation function. They
also provide a first estimate the mass density of the Universe $\Omega_M$
and of the normalisation of the mass power spectrum $\sigma_8$, which are
in agreement with the cluster abundance constraints.

{\bf van Waerbeke}, {\bf Pen}, and Mellier (IAP) have investigated the
decomposition of shear maps into $E$ (Electric, i.e. curl free) and $B$
(Magnetic, i.e. curl) modes. Gravity predicts only $E$ mode to be
non-zero on shear maps. Any $B$ mode detection is an indication of the
residual systematics amplitude in the data (either Point Spread
Function correction residuals and/or intrinsic alignement
effects). They find that the B mode contributes at most $20\%$ of the $E$
mode, which indicates a low level of residual systematics. Tools are
developed which allows a fast and accurate computation of the
different statistics from the shear 2-point function alone, as well as
their noise matrices.

{\bf van Waerbeke}, M. White (Berkeley), and J. Mackey (CfA) are
investigating the statistics of peaks detected in shear maps. They
have used ray-tracing numerical simulations to study how accurately
the cluster mass function could be recover, from lensing selected
peaks in a lensing survey. They have reached the pessimistic
conclusion that the measured statistic suffers from several biases
mixing observational and cosmological issues.

\subsection{Galaxies and Dynamics}

{\bf Dubinski} and summer student Pritchard have developed a new code for
following the evolution of systems of gravitating colliding hard
spheres for studies of planetesimal accretion in the terrestrial
region, planetary rings and asteroid and planetary collisions. The
code has been tested on systems containing millions of particles and
should push the field into a new regime of high resolution.

Robin {\bf Humble} and collaborators have added a dusty gas phase model to a
parallel asynchronous Smoothed Particle Hydrodynamics and N-body Tree
code to enable direct modelling of dusty protoplanetary disks. Various
gas-dust drag terms, viscosity formulations, initial conditions, dust
masses and radii, and thermal properties of the gas disks are explored
in order to determine the regime appropriate to planet
formation. These are compared with linear analytic determinations of
gravitationally instability timescales and modes.

It has been widely noted that the parent stars of planetary systems
are metal rich. N. {\bf Murray}, together with B. Chaboyer (Dartmouth) have
been trying to decide if the high metallicities seen are primordial,
or whether the stars have accreted metal rich material after reaching
the main sequence. The best evidence that at least part of the effect
is due to accretion is that the low mass stars that have planets are
not as metal rich as the high mass stars with planets, as {\bf Murray} and
Chaboyer show. However, they point out that two selection effects,
based on apparent V magnitude (it is hard to get good radial
velocities for dim stars) and color (the current surveys discriminate
against blue stars, since they have too few lines to determine radial
velocity) could combine to produces this mass-dependent effect.

Unlike the planets in our solar system, most of the extrasolar planets
discovered so far have very elongated, eccentric orbits. Furthermore,
most of the extrasolar planets orbit much closer to their parent
stars; apparently, they formed at distance comparable to the
separation between Jupiter and the sun, and subsequently migrated
inward. N. {\bf Murray}, M. Paskowitz (CITA), and M. Holman (Harvard-CfA)
have proposed that the large eccentricities arise as the migration
proceeds.  The migrating planets, which have masses comparable to
those of Jupiter, capture smaller bodies and force them to migrate in
lock step. The gravitational interactions between the two planets then
drive up the eccentricity of both bodies.

Following up on a paper that appeared in Science magazine, B. Hansen
(Princeton/UCLA), N. {\bf Murray}, and M. Holman (Harvard-CfA) have been
studying the interaction of a Jupiter mass planet with a massive
planetesimal disk. Numerical simulations involving only two body
interactions show that the massive planet efficiently ejects the
smaller planetesimals, leading to an inward migration of the Jovian
body. Simulations including several Jupiter mass bodies exhibit a
variety of behaviors, depending on the initial location and mass of
the large bodies. In most cases the planets repel each other, but in
others two massive bodies may approach each other. In the latter case,
the two planets may be locked into a resonance, so that both migrate
inward keeping a fixed ratio of orbital periods.

It is widely believed that the asteroid belt originally contained 2-4
Earth masses of material; today it contains less than a Lunar
mass. Mechanisms for the removal of this mass are not in short supply,
but they all involve dropping about half the original mass onto the
sun several hundred million years after the formation of the solar
system. The surfaces of the terrestrial planets bear mute testimony to
this process. A second indication that such a process occurred would
be that the solar convective envelope, which has a mass only 2% that
of the sun, would have a slightly higher iron abundance than the solar
interior. Unfortunately, this enhancement is too small to be detected
by helioseismology. N. {\bf Murray}, together with B. Chaboyer (Dartmouth),
P. {\bf Arras} (CITA), B. Hansen (Princeton/UCLA), and R. W. Noyes
(Harvard-CfA) realized that, if a similar process occurred around
other stars, then those stars with smaller convection zones than the
sun should appear more metal rich than stars with more massive
convection zones. By looking at the spectroscopically determined iron
abundances of 466 main sequence stars, they showed that such a
stellar-mass dependent trend appears to be real, indicating that most
stars in the solar neighborhood have accreted about one-half an Earth
mass of iron.

Norm {\bf Murray} has written a pedagogical article for Physics in Canada,
describing recent advances in the understanding of chaotic motion in
the solar system.

Norm {\bf Murray} and M. Holman have written an invited review article for
Nature, describing recent advances in our understanding of chaotic
motion in the solar system.

Norm {\bf Murray} with M. Lecar, F. Franklin, and M. Holman, has written an
article for Annual Reviews which uses a simple analytic theory to
explain why the planets are chaotic, and gives examples of chaotic
motion in the asteriod and Kuiper belts, and in the motion of
planetary satellites.

Among the 70 or so known extra-solar giant planets, many are so close
to the host star that tidal dissipation have circularized their
orbits. However, planet HD 83443b has the smallest semi-major axis yet
has a substantial eccentricity. {\bf Wu} and Goldreich (Caltech) have found
that this is a result of forcing by the second, further out planet
found in the system. Secular interactions combined with tidal
evolution have delivered the two planets into periaps alignment, with
eccentricities proportional to each other. The observed ratio of the
two eccentricities can be reproduced, but only if one includes
precessions due to general relativity, due to quadrupolar distortions
related to tide and planet rotation. The authors also infer that the
inner planet, with roughly Saturn mass, has to be at least as large as
Jupiter. Moreover, the unique evolutionary state of this two-planet
system allows one to constrain the rate of tidal dissipation in
exoplanets.

\subsection{The Interstellar Medium}


%Studies of the interstellar medium (ISM) address the diffuse gas and
%dust between stars, and their role in the life cycles of stars and of
%galaxies.  Derived from the infall of gas from intergalactic space,
%the ISM is the substrate from which stars condense and into which
%stellar winds and supernovae expand.  All aspects of galactic
%evolution -- the way galaxies appear from afar, the rate at which they
%form stars of various types, and the manner in which they intensify
%their internal magnetic fields -- are manifestations of how the ISM
%reacts to internal forces (e.g., supernovae) and to external forces
%(e.g., collisions between galaxies).  Despite fifty years of progress,
%many open questions remain: for instance, how do newborn stars affect
%the gas clouds from which they formed?  What is the mechanism by which
%dust grains align with the magnetic field?  How can this effect be
%used to interpret observations of dense, cold molecular clouds?  What
%are the basic dynamics and structure of these objects, from which
%stars form?  In 2001, CITAzens have been addressing these questions
%with techniques ranging from fundamental physics, to analytical and
%numerical modeling of important phenomena, to the detailed
%investigation of individual regions, as outlined below.

{\bf Fiege}, Matthews (McMaster) and Wilson (McMaster)
have re-analyzed 850 micron SCUBA polarization data of OMC-3 region
of the Orion A molecular cloud using improved 
software that was not available in 1998, when the data were 
taken.  This region contains a bright filament that is partially
fragmented into cores.  Strong depolarization was observed 
toward the cores and along the spine of the filament.  The 
polarization structure was modelled in detail using the 
technique outlined by Fiege and Pudritz (Ap.J, 2000, 544, 830),
using their helical field model (Fiege \& Pudritz, 2000, MNRAS,
311, 85).  Excellent agreement with the data was obtained
by bending the bottom part of the filament into a circular arc,
and transforming the magnetic field self-consistently.

{\bf Fiege}, Matthews and Moriarty-Schieven (JCMT) have used
SCUBA polarimetry to map 3 star-forming systems of 
cores in Orion B.  All 3 regions were found to contain 
polarization patterns that were indicative of highly ordered
but non-uniform magnetic fields.  Depolarization was found 
toward the bright cores in all 3 regions.  NGC 2024 was the
brightest and most interesting region mapped.  2 different 
models were proposed to account for the polarization data, and
artificial polarization maps were computed for each model.  Good
agreement was found for a Fiege \& Pudritz (2000, MNRAS, 311, 85)
helical field model.  Reasonable agreement was also found for a 
second model, in which the polarizing gas was assumed to be confined 
to a paraboloidal shell wrapped around the filamentary structure
in NGC 2024.  While the first model better explained the 
polarization data, the second model was in better agreement with 
existing independent Zeeman data.

Using an 850 micron SCUBA map of the dark globule CB068 -- 
which contains a Class 0 Young Stellar Object (YSO) and an
associated bipolar outflow -- {\bf Fiege}, Vallee (Herzberg)
and Greaves (JCMT) have constructed a polarization model
based on the Fiege \& Pudritz model  (2000, Ap.J., 534, 291) 
of magnetized prolate cores.

The formation and collapse of a protostar involves the 
simultaneous infall and outflow of material in the 
presence of magnetic fields, self-gravity and rotation. 
{\bf Fiege}, in collaboration with Aburihan and Henriksen (Queens)
and Lery (Dublin IAS), has used self-similar techniques to
model self-consistently the anisotropic collapse and outflow.  
An exact, analytical solution was found, which may describe
the simultaneous infall and outflow in young, magnetized protostars.

Powerful, highly collimated jets, surrounded by bipolar 
molecular outflows, are commonly observed near Young 
Stellar Objects (YSOs).  The existing class of circulation
models (Fiege \& Henriksen, 1996, MNRAS, 281, 1038; 
Lery et al. 1999, AA, 350, 254) was extended by {\bf Fiege}
and collaborators Lery, Henriksen, Ray (Dublin IAS), Frank
(Rochester) and Bacciotti (Arcetri).  The new models involved
joining together piecewise solutions for an accreting protostellar
disk, a jet, and a wide-angle circulation region at intermediate
polar angles.

{\bf Fiege} \& Henriksen are addressing the role of self-gravity in
very young protostellar outflows, which often contain much
more mass than the star forming at the centre.  Their previous
models used a central point mass and neglected self-gravity in
the surrounding gas.  Thus, the new models apply to a much 
younger stage of evolution.  Early results indicate that
the inclusion of self-gravity results in much more powerful
outflows than have been found in their earlier central mass 
dominated circulation models.

{\bf Fiege} \& Lyutikov (McGill) are developing a time-dependent, 
self-similar model for the toroidal field driven formation 
and collapse of filamentary molecular clouds, taking into 
account self-gravity, magnetic fields, turbulent wave 
"pressure", and the dissipation of turbulence.  
Lyutikov \& {\bf Fiege} are working on a model for the injection
of turbulent energy into the toroidal field-dominated
filamentary molecular clouds.  The basic idea is that m>1 
instabilities develop, which may lead to reconnection events,
forming closed loops of toroidal flux.  These sink though 
the plasma stirring up the turbulence in the process.
Meanwhile, toroidal flux leaks into the filament from the
surrounding gas to replenish the lost flux.


{\bf Martin} is a permanent member of the scientific management of the Canadian Galactic Plane Survey, now expanded to form the International Galactic Plane
Survey (IGPS). CGPS II is being carried out at the Dominion Radio Astrophysical Observatory and the newest thrust is an H I survey of the inner Galactic plane
(first quadrant) using the Very Large Array (VLA). Rothwell has managed to carry out a lot of data reduction and has produced the first mosaiced spectral line
data cubes in the H I line. Continuum mosaics from the end spectral channels are being used with infrared data to classify newly resolved continuum sources,
some of which are supernova remnants. 

The IGPS data base, covering all important constituents of the ISM, is
particularly well suited to probing the responses of the ISM to the
formation of massive stars. As part of her thesis with {\bf Martin}, 
Karr (Toronto) has undertaken
a major development of ``intelligent'' (pipeline) code for an
extensive analysis of IGPS emission-line and continuum data. Her major
goal is a statistical analysis of triggered star formation. A
sidelight of her work has been production of a catalog of CO clouds
which allows examination of how the size-linewidth relations in star
forming regions compare to those from focused studies of more
quiescent regions.

Compared to infrared images of star forming regions, submillimetre
observations can reveal colder clouds of dust (and gas) in early
stages of pre-stellar collapse.  With JCMT/SCUBA observations of the
KR 140 region {\bf Martin}, Kerton (Herzberg), Johnstone (Toronto), and
Ballantyne (Cambridge) have discovered a number of relatively cold
submillimetre sources not visible in the IRAS data, ranging in size
from 0.2 to 0.7 pc and in mass from 0.5 to 130 Msun. Several of the
submillimetre sources are found at the H II molecular gas interface
and have probably been formed as the result of the expansion of the H
II region. Many of the submillimetre sources are gravitationally bound
and most of these follow a mass-size relationship expected for objects
in virial equilibrium with nonthermal pressure support. Interestingly
then, not all stars in this region form at the same time.

{\bf Martin}, Kerton and colleagues are examining the evolution of
interstellar dust by exploiting the fact that different dust
components have characteristic spectral emissivities. The
HIRES-processed MIGA mosaics at 12 and 25 microns produced by Kerton
and {\bf Martin} trace transiently heated grains and PAH molecules and can
be compared to complementary mosaics from data from the MSX mission
and data anticipated from SIRTF. While MIGA provides a significant
improvement in both resolution and image quality over previous IRAS
infrared image products, the characteristics of the HIRES beam make
accurate comparisons between the various IRAS bandpasses and between
HIRES data and data at other wavelengths nontrivial. Kerton and {\bf Martin}
have presented a new, fast technique for the construction of HIRES
beam-matched images that is especially well suited for the creation of
large-scale (several square degree) ratio maps.

Key dust properties, like size distribution and chemical composition,
show remarkable changes in different phases of the ISM. Far
ultraviolet data from FUSE and HST on the extinction of starlight are
being used by {\bf Martin}, Wolff (SSI), and Clayton (LSU) to probe and
constrain the properties of the small dust grains, such as abundance
and size, and their connection to the very different environments
observed. They are examining several types of sightline which possess
distinct signatures associated with the small grain population and
whose mid-UV extinction curves reveal vastly differing amounts of
intermediate-sized particles.

The Orion Nebula is important in itself as a nearby star forming
region, and because it provides a relatively simple nebular
environment to test complex simulations. {\bf Martin} is working intensely
with a group (E. Verner, D. Verner and G. Ferland, Kentucky;
J. Baldwin, MSU) investigating the Orion Nebula to derive a realistic
model for the interaction geometry, dynamics, and emission-line
spectrum. In this particular study, Verner and colleagues have
identified the pumping routes that are responsible for the 40 [Fe II]
emission lines that they have identified in recent high resolution and
high signal to noise spectra.

Blagrave (Toronto), {\bf Martin} and colleagues are using deep echelle
spectra of the Orion Nebula to determine the line strengths and
motions of key ions of oxygen, nitrogen, silicon, and iron. These
sensitive measurements are making it possible to evaluate
self-consistent models for the excitation mechanisms (fluorescence,
recombination) of the faint permitted lines, the dynamics of the
nebula, and its ionization structure.

Blagrave, {\bf Martin} and colleagues have been focusing on what can be
learned by combined analysis of co-spatial spectra from the
ultraviolet, optical, and mid-infrared spectral regions. Modeling is
being carried out using the photoionization code Cloudy to derive a
realistic model for the interaction geometry, dynamics, and the entire
emission-line spectrum. A thorough examination of abundances in the
Orion Nebula will provide a critical benchmark for understanding
distant extragalactic H II regions.

Rubin (NASA Ames), Ferland, {\bf Martin} and colleagues have used HST/WFPC2
imagery for the planetary nebula (PN) NGC 7009 to evaluate the
electron temperature (Te) and the mean-square Te variation across the
face of the nebula. The preliminary map Te is rather uniform; almost
all values are between 9000 -- 10500 K, with the higher Te's closely
coinciding with the inner He++-zone.

Unique diagnostics of the density, temperature, and velocity field in
regions of star formation are provided by the quadrupole emission
lines of molecular hydrogen (H2). Interpretation depends critically on
collisional rate coefficients which {\bf Martin}, Mandy (UNBC) and
colleagues are calculating using quasiclassical trajectory
techniques. As different reactions are explored, depending on
different potential energy surfaces, it is important to check the QCT
calculations where possible with quantum calculations (low energy
and/or restricted geometry). This paper presents QCT calculations for
the H2 + H2 system (H4 potential energy surface), contrasting the
vibrational excitation behaviour seen in three restricted geometries.

Boothroyd (Caltech), {\bf Martin}, and colleagues have completed their most
recent potential energy surface (PES), in this case for the
interaction of molecular hydrogen (H2) with H2. This 400-parameter fit
spanning 6-dimensions was constrained by 48180 ab initio energies,
42079 newly calculated for this study. This PES represents a
significant improvement over previous H4 surfaces, having an
energy-weighted rms error of 1.15 millihartree relative to the 48180
energies, comparable to the estimated error in the energies
themselves. The new PES also fits the van der Waals well to an
accuracy of about 5%.

Boothroyd and {\bf Martin} are completing a new potential energy surface for
the interaction of helium with molecular hydrogen (He-H2) based on a
large grid of ab initio energies they have calculated. The analytical
fits optimized so far represent significant improvements over previous
surfaces, having rms errors comparable to the estimated errors in the
ab initio data. This will provide a sound basis for calculations of
collisional rate coefficients.

Chris {\bf Matzner} has argued that massive stars are the dominant sources
of energy for the turbulent motions within giant molecular clouds, and
that the primary agent of feedback is the expansion of H II regions
(ionized nebulae). His work shows that the properties of the giant
molecular clouds can be understood as an equilibrium between the input
of energy by H II regions and its decay in turbulent motions, despite
the fact that turbulence decays very rapidly. Such an equilibrium
implies an evaporation rate, and therefore a lifetime, for
clouds. This may explain the maximum cloud mass, since larger clouds
would self-destruct more rapidly than they can be assembled. Clouds
cannot be supported by H II regions in the high-pressure environments
of starburst galaxies, and this may be related to the formation of
massive star clusters in those galaxies.

{\bf Pogosyan} and A. Lazarian (Wisconsin) have addressed a long-standing
problem of obtaining statistics of interstellar turbulence from
observational data using HI data as a test case of an optically thin
line for which good data sets exist. They obtained the analytical
description of the emissivity statistics in channel maps and on this
basis developed a technique that allows to separate the contributions
from density and velocity. The technique accounts both for turbulent
and thermal velocities of emitting atoms. Together with
Vazquez-Semadeni they successfully tested the technique using
numerical simulations of compressible MHD flow.  Their technique has
been already applied to the Galactic and Small Magelanic Cloud data
and it opens wide avenues for future research aimed at understanding
interstellar turbulence.

Already in 1959, cosmic Rays have been suspected as having a climatic effect on Earth. A more recent discovery has shown that the
galactic cosmic ray flux reaching Earth (which is modulated by the solar wind) is highly correlated with the low altitude cloud cover. This
has led {\bf Shaviv} to propose that passages through the galactic spiral arms, are responsible for the almost periodic appearances of ice-age
epochs on Earth (each 150 Million years or so) -- each time a spiral arm is crossed, a higher cosmic ray flux is responsible for a higher
low altitude cloud cover and a reduce global temperature. Ample evidence was found to corroborate this picture: The expected periodicity
in the spiral arms crossings, the periodicity observed in the cosmic ray flux variations as extracted from Iron meteorites and the periodicity
observed in past Earth glaciation epochs all agree in period and in phase. Moreover, longer term global climate variations -- such as the
lack of glaciations between 1 and 2 billion years ago or their appearance between 2 and 3 billion years ago, were also found to correlate
with the average star formation rate in the Milky Way. 

{\bf van Hoof}, Ferland, {\bf Martin}, {\bf Weingartner} and Volk (Calgary) have nearly
completed the first major upgrade of the grain model in the
photoionization-modelling code, Cloudy. Essentially every part of the
code has been rewritten, resulting in a code that is much more
flexible and yields more realistic predictions. The grain physics have
been upgraded to the current state of the art. The user will notice
the following improvements in the grain model. First, a Mie code for
spherical particles has been included, giving the user complete
freedom in choosing grain properties and size distributions. Second,
size distributions can now be resolved to arbitrary precision, and
physical properties are calculated for each bin separately. Third,
non-equilibrium heating of the grains is now treated correctly for
each size bin. A new grain charge model has been developed for Cloudy
(CITA-2001-18). This new model enables a flexible approach to
resolving the grain charge distribution. It allows the code to be
efficient, while retaining sufficient accuracy at the same time. A
refereed journal article applying the new model to the silicate
emission in the Ney-Allen nebula is currently in preparation.

{\bf Weingartner} and B.T. Draine (Princeton) have constructed size
distributions for carbonaceous and silicate grain populations in
different regions of the Milky Way, LMC, and SMC. These distributions
include sufficient very small carbonaceous grains (including
polycyclic aromatic hydrocarbon molecules) to account for the observed
infrared and microwave emission from the diffuse interstellar medium,
and also reproduce the observed extinction of starlight, which varies
depending upon the interstellar environment through which the light
travels. For several size distributions, they have evaluated the
albedo and scattering asymmetry parameter, and have constructed model
extinction curves extending beyond the Lyman limit.

{\bf Weingartner} and B.T. Draine (Princeton) have modelled the
photoelectric emission from and charging of interstellar dust,
obtaining photoelectric gas heating efficiencies as a function of
grain size and the relevant ambient conditions. Using their
recently-constructed grain size distributions, they evaluated the net
gas heating rate for various interstellar environments, finding less
heating for dense regions than for diffuse regions. As one application
of the model, they have found that photoelectric heating by dust can
account for the observed variation of gas temperature with distance
from the galactic midplane in the warm ionized medium.

{\bf Weingartner} and B.T. Draine (Princeton) have modelled the forces on
grains exposed to anistropic radation, due to the anisotropic emission
of photoelectrons and photdesorbed adatoms. The "photoelectric" force
depends on the ambient conditions relevant to grain charging. They
find that this force is comparable to the radiation pressure when the
grain potential is relatively low and the radiation spectrum is
relatively hard. They adopt a simple, yet plausible, model for the
surface physics and chemistry and find that the "photodesorption"
force dominates the radiation pressure for grains larger than 0.1
microns exposed to starlight from OB stars. They also find that the
anisotropy of the interstellar radiation field is of order 10% in the
visible and ultraviolet. They estimate size-dependent drift speeds for
grains in the cold and warm neutral media and find that micron-sized
grains could potentially be moved across a diffuse cloud during its
lifetime.

With the high-resolution spectroscopy now available in the optical and
satellite UV, it is possible to determine the neutral/ionized column
density ratios for several different elements in a single
cloud. Assuming ionization equilibrium for each element, one can make
several independent determinations of the electron density.  For the
clouds for which such an analysis has been carried out, these
different estimates disagree by large factors, suggesting that some
process (or processes) besides photoionization and radiative
recombination might play an important role in the ionization
balance. One candidate process is collisions of ions with dust
grains. Making use of their recent work quantifying the abundances of
polycyclic aromatic hydrocarbon molecules and other grains in the
interstellar medium, as well as their recent models for grain
charging, {\bf Weingartner} and B.T. Draine (Princeton) have estimated the
grain-assisted ion recombination rates for several astrophysically
important elements. They found that these rates are comparable to the
rates for radiative recombination for conditions typical of the cold
neutral medium. Including grain-assisted ion recombination in the
ionization equilibrium analysis leads to increased consistency in the
various electron density estimates for the gas along the line of sight
to 23 Orionis. However, not all of the discrepancies can be eliminated
in this way; they have speculated on some other processes that might
play a role. They also noted that grain-assisted recombination of H$^+$
and He$^+$ leads to significantly lower electron fractions than usually
assumed for the cold neutral medium.

{\bf Weingartner} and B.T. Draine (Princeton) continue investigations of the
alignment of grains with the interstellar magnetic field. Current work
focuses on generalizing their previous treatment of the dynamics of
irregular grains subject to torques due to the anisotropic starlight
radiation field. With the new treatment, the evolution through periods
of relatively slow grain rotation ("crossovers") can be followed. This
will make possible a systematic study of the alignment efficiency as a
function of grain size, shape, and composition. With these results,
the model can be tested against observations of the wavelength
dependence of starlight polarization.

\subsection{High Energy Astrophysics and Stellar Physics}

In rapidly rotating neutron stars, oscillation modes such as R-modes
can become overstable through the emission of gravitational waves. The
rotational energy of the star must be tapped in order to drive the
mode and, as a result, the star can be spun down in a relatively short
time. The gravitational radiation may be detected by LIGO. This
mechanism has been proposed to limit the spins of accreting neutron
stars in LMXB's, as well as rapidly rotating young neutron stars. A
key parameter is the saturation amplitude of the mode. {\bf Arras}, in
collaboration with K. Schenk (UCSF), I. Wasserman, S. Teukolsky and
E. Flannagan (Cornell) and S.  Morsink (Alberta) are studying the
nonlinear coupling of oscillation modes as a means of saturating the
instability. When the R-mode reaches a critical amplitude, it will
transfer energy to other modes at a rate which matches the driving
rate. A simple estimate for the resulting saturation amplitude of the
mode is (very roughly) 1/kappa*Q, where kappa is the size of the
dimensionless interaction energy between modes and Q is the quality
factor of the damped mode which couples to the R-mode. To obtain a
more precise numerical result, {\bf Arras} et al. are currently performing
more detailed calculations of the nonlinear coupling, damping, and
driving for the relevent modes.

{\bf Arras} et al. have developed the mathematical formalism necessary to
study linear and nonlinear oscillation modes in rotating stars,
including the inertial modes and the usual p, g or f-modes. In
rotating stars, the addition of the Coriolis force gives rise to a
quadratic eigenvalue problem which determines the mode frequency and
displacement field. The resulting oscillation modes are not orthogonal
with respect to the usual inner product, and so a new inner product is
devised. The time-dependent velocity field is then expanded in terms
of the eigenmodes, and time-dependent equations for the expansion
coefficients are found (correctly for the first time). {\bf Arras} et
al. have also derived formulae for the lowest-order nonlinear coupling
between fluid waves in rotating stars. Several selection rules are
identified governing the three-mode coupling of inertial waves. A
time-dependent mode amplitude equation, including nonlinear coupling,
is identified which can be put in a closely analogous form as in the
case of a non-rotating star. Finally, the authors present an efficient
numerical method for computing the nonlinear coupling coefficients.

There is one instance of a very weak gamma-ray burst (GRB)
compellingly associated with a very enegetic supernova (SN). {\bf Matzner},
Tan (Princeton), and McKee (Berkeley) propose that the GRB is a
natural side product of such an over-energetic explosion, if the
exploding star was compact and possessed a relatively dense stellar
wind. For this to happen, a fraction of the SN energy must be
channelled into relativistic ejecta as the SN shock front accelerates
down the density gradient in the outer stellar envelope (as in the
crack of a whip). Tan et al. study the process of shock acceleration
across the transition to relativistic motion, and the continuing
acceleration of ejecta as they expand into the region around a star,
finding that previous works greatly underestimated the available
energy of such ejecta. Also considered are the explosions of
hypothetical ``hypernovae'' of extremely high energy, as well as the
ejection of material from collapsing white dwarfs and neutron stars.

Mikhail {\bf Medvedev} and Ramesh Narayan (Harvard) have discovered a new
type of a hot, optically thin accretion flow onto a rapidly rotating
neutron star or another compact object with a surface. This flow,
called the "Hot Settling Flow", extracts rotational energy of the
central star by viscous braking and radiates it via free-free
emission. Unlike all other known accretion flows, the structure of a
Hot Settling Flow and its luminosity are independent of the mass
accretion rate, thus the flow may have a very large efficiency. The
flow is cooling-dominated; it is convectively stable and may not have
outflows. These results were confirmed by numerical models.

Mikhail {\bf Medvedev} and Ramesh Narayan (IAS \& Harvard) studied thermal
conduction effects in hot accretion flows. Such flows are
collisionless systems (because of a low density and a large
temperature), thus the Spitzer theory fails. A theory of collisionless
thermal conduction in tangled (MHD turbulent) magnetic field was
considered. In application to known cooling-dominated (and hence
thermally unstable) accretion flows, they demonstrated that thermal
conduction cannot stabilize the Shapiro-Lightman-Eardley flow, but the
newly discovered Hot Settling Flow is thermally stable in the presence
of thermal conduction. This is crucial to prove that the flow can
exist in nature.

Mikhail {\bf Medvedev} and Norman {\bf Murray} are studying the possibility that a
Hot Settling Flow may form around a rapidly rotating black hole. The
flow is torqued by a black hole via the Blandford-Znajek
mechanism. Hence, it is natural to expect jet outflows in such systems
as well. The model is applied to the galactic micro-quasars and dim
galactic nuclei.

Mikhail {\bf Medvedev} and Kristen Menou (Princeton) are studying the
properties of hot accretion flows in several binary systems with a
white dwarf as a primary, which experience regular outbursts separated
by long quiescent phases. The study utilizes a numerical code written
by {\bf Medvedev}. Preliminary results indicate that a purely
advection-dominated flow never forms, regardless of the star spin,
whereas a hot settling flow exists around white dwarfs with
sub-Keplerian rotation. The X-ray luminosity is a good indicator of an
accretion rate in systems with slowly spinning stars, only.

In a series of papers Mikhail {\bf Medvedev} elaborated the structure and
properties of ultra-relativistic shocks which produce both prompt
gamma-ray emission and delayed afterglows. He used the kinetic theory
of plasma instabilities to demonstrate inevitable production of strong
magnetic fields in such shocks and discussed their effects. He also
elaborated the radiation mechanism operating in gamma-ray burst (GRB)
shocks. He demonstrated that the synchrotron mechanism is unlikely
given the structure of the shock and properties of the magnetic
field. A newly discovered "Jitter" mechanism naturally explains
several puzzles of spectra of prompt gamma-ray emission.

Mikhail {\bf Medvedev} and George Rybicki (Harvard) finished the study of
some very non-trivial properties of polytropic, self-gravitating
systems. Such polytropes are often used as models of molecular clouds
and stars. In particular, they found an approximate analytical
solution of the Lane-Emden equation with the polytropic index close to
5. They also presented a continuous fraction approximation of a full
solution.

N. {\bf Murray} is one of a large number of workers involved in several
observational efforts aimed at understanding outflows in quasars. For
example, together with N.  Arav (UC Berkeley) and others, he undertook
a long STIS observation of PG 0946+301, a broad absorption line
quasar. The absorption lines are not black, but they are clearly
saturated, indicating that the outflow does not cover the continuum
source. Consequently, the total column density of absorbing gas is
much larger than would be inferred by a simple calculation of the
optical depth based on the fraction of the continuum that is
absorbed. The implication is that the outflow is much more massive
than previous studies indicated, and more consistent with the large
columns found by studies of broad absorption line quasars in the x-ray
band.

{\bf Shaviv} has been interested in luminous atmospheres shining close to
and beyond the Eddington limit--The luminosity above which radiation
pressure should be larger than the Gravitational pull. It was found
that a super Eddington steady state could exist provided that
inhomogeneities exist to reduce the effective opacity.  This porosity
naturally arises even in Thomson scattering atmospheres which were
found to be unstable as they approach the Eddington limit. These super
Eddington configurations were also found to have a predictable
optically thick wind. This was applied successfully to explain the
observed mass loss in classical nova eruptions and in the great
eruption of the massive star eta Carinae. When combining the porous
atmospheres with complete stellar structure equations incorporating
nucleosynthesis, it was found that the core-mass-luminosity relation,
which describes the luminosity of a degenerate object with shell
burning Hydrogen, obtains a super-Eddington branch with a porous
atmosphere. This branch naturally explains the super Eddington
behavior seen in classical novae.

{\bf Shaviv} and Heyl (Harvard) have been interested in the QED effects that
the highly magnetized vacuum around neutron stars has on the
propagation of photons.  Since the vacuum is birefringent, the
polarization state of photons evolves 'adiabatically' near the neutron
stars. That is, a high energy photon (generally UV and beyond) emitted
in one polarization state relative to the magnetic field direction
will keep its polarization state up to a distance larger than the
radius of the neutron star. The net result is that the vacuum
birefringence tends to align together the polarization of the
photons. Without it, the highly polarized light emitted from different
surface elements will add up 'incoherently', to yield a small observed
polarization. With the polarization alignment, large net polarizations
are obtained.  This allows more information to be extracted on the
NSs. For example, the circular polarization obtained yields
information non dipolar fields.

{\bf Thompson} and {\bf Murray} have considered the amplification and transport of
a magnetic field in the collapsed core of a massive star, including
both the region between the neutrinosphere and the shock, and the
central, opaque core. A dynamical balance between turbulent and
magnetic stresses within convective layers (both inside the star, and
in the accreting envelope material) leads to flux densities of order
ten to the fifteenth Gauss. Buoyant motions of magnetized fluid are
greatly aided by the intense neutrino flux, and are calculated in the
various regions of the core. The implications of these results for
pulsar magnetism were investigated and applied to the case of late
fallback over the first one thousand to ten thousand seconds of the
life of a neutron star.

{\bf Thompson} and Robert Duncan (U. Texas Austin) made a detailed
comparison of the magnetar model with the extraordinary
X-ray/gamma-ray flare recorded from the Soft Gamma Repeater 1900+14 on
August 27, 1998. They proposed a triggering mechanism, whereby a
helical distortion of the core magnetic field induces large-scale
fracturing in the crust and a twisting deformation of the crust and
exterior magnetic field. The envelope of the pulsating tail of the
August 27 flare can be accurately fit, after $\sim$ 40 s, by the contracting
surface of a relativistically hot, but inhomogeneous, trapped
fireball. The effects of direct neutrino-pair emission were
quantified, thereby deducing a lower bound $\sim 10^{32}$ G-cm$^3$ to the
magnetic moment of the confining field. The radiative flux during the
intermediate $\sim 40$ s of the burst appears to exceed the trapped fireball
fit -- probably as the result of continuing seismic activity. This
motivated a detailed analysis of the thermal stability of a confined
thermal pair plasma in a super-QED magnetic field, and the critical
heating rate above which there is a runaway to an ultrahot plasma (T $\sim$
1 MeV) in local thermodynamic equilibrium. In the later pulsating
tail, the best fit temperature equilibrates at a value which agrees
well with the regulating effect of photon splitting. The remarkable
four-peaked substructure within each 5.16-s pulse provides strong
evidence for the presence of higher magnetic multipoles in SGR
1900+14. The corresponding collimation of the X-ray flux has been
related to radiative transport in a super-QED magnetic field.

{\bf Thompson}, Maxim Lyutikov (McGill) and Shri Kulkarni (Caltech) have
calculated the structure of a neutron star magnetosphere which is
threaded by large-scale electrical currents, and the effect of
resonant Compton scattering by the charge carriers (both electrons and
ions) on the emergent X-ray spectra and pulse profiles. In the
magnetar model for the SGRs and AXPs, these currents are maintained by
magnetic stresses acting deep inside the star. They show, by
constructing force-free equilibria with a power law dependence of
magnetic field on radius, $B \propto r^{-2-p}$, that a large-scale
twist softens the radial dependence to $p < 1$. The spindown torque
acting on the star is thereby increased in comparison with a vacuum
dipole, and the polar field deduced from spindown measurements might
be reduced by a factor 3-10 with respect to a vacuum dipole in some of
the SGR and AXP sources. Consideration of the stability of the twist
may provide an explanation for the narrow measured distribution of
spin periods. A magnetosphere with a strong twist has an optical depth
$\sim 1$ to resonant cyclotron scattering at the magnetic equator,
independent of frequency (radius), surface magnetic field strength, or
charge/mass ratio of the scattering charge.  When electrons and ions
supply the current, the stellar surface is also heated by the
impacting charges at a rate comparable to the observed X-ray output of
the SGR and AXP sources, if the polar dipole field is $\sim 10^{14}$
G. Redistribution of the emerging X-ray flux at the ion and electron
cyclotron resonances will significantly modify the emerging pulse
profile. The non-thermal spectral tail generated through the Doppler
effect is being calculated using a Monte Carlo approach. The sudden
change in the pulse profile of SGR 1900+14 after the 27 August 1998
giant flare is related to an enhanced optical depth to electron
cyclotron scattering, resulting from a sudden twist imparted to the
external magnetic field.

{\bf van Hoof} has continued a long-term collaboration with G. Van de Steene
(RO Belgium), Peter Wood (RSAA Australia), P. {\bf Martin} and G. Ferland
(Kentucky), to establish a sampleR of infrared-selected post-AGB stars
and study their properties. In 2000 and 2001 papers were published
discussing near-infrared spectroscopic and photometric observations of
these objects (CITA-2000-31, CITA-2000-59). A paper discussing the H
alpha (an optical atomic transition of hydrogen) P-Cygni profiles (a
type of emission line indicating severe mass loss) in some of these
objects was published as well, refuting the commonly held idea that
the wings in these lines were caused by electron scattering
(CITA-2000-47). They recently obtained high-resolution echelle spectra
with UVES on the VLT at ESO Paranal. Analysis of these data is
currently underway, and will be aimed at obtaining mass loss
parameters for these objects. Only very few post-AGB stars have known
mass loss rates, and this sample will be a valuable addition.

Yanqin {\bf Wu} and P. Goldreich (Caltech) have recently made some
significant progress toward understanding the saturation of pulsations
in a broad range of variable stars. They have found some simple
scaling relations that discriminate between stars that have large
pulsation amplitudes (RR Lyraes, Cepheids, Miras, etc.) and stars that
do not (white dwarfs, subdwarf-B stars, some $\delta$-Scuti stars,
rapidly oscillating Ap stars, etc.). These scaling laws arise from the
ability or inability for an unstable modes to couple effectively to
damped modes. Stars that have large central-to-mean density ratios
(giants) are likely to have large pulsation amplitudes, while those
with mall ratios (dwarfs) should display small amplitudes. These
results compare well with observations and are being prepared for
publication.

{\bf Wu} and van der Swaluw (Belfast) have proposed a method to infer the
initial spin periods of radio pulsars residing in composite supernova
remnants. This type of remnant consists of both a plerionic and a
shell-type component, corresponding to the pulsar wind nebula driven
by the spin-down luminosity of the central pulsar, and the blast wave
bounding the supernova remnant. At some 1000-10,000 yrs after birth, a
simple scaling law connects the relative radii of the two components
with their relative energy content. One can use this scaling law to
estimate the initial spin periods of pulsars residing in composite
remnants, since the energy content of the plerion depending on the
initial spin periods. Their analysis show that all pulsars in their
sample are likely born with spin-rates well below break-up, and an
early braking mechanism like r-mode instability is unlikely to
operate.

Gamma-Doradus variables are early F-type dwarfs that pulsate with
periods from 0.4 to 3 days, and with amplitudes below 0.1
magnitude. The pulsations are associated with non-radial
gravity-modes. Yanqin {\bf Wu} has shown that surface convection zones in
these variables can drive pulsation via the `convective driving'
mechanism. This mechanism was first proposed and studied in the
context of ZZ Cetis (hydrogen-envelope white dwarfs with g-mode
pulsations) by Brickhill (1991) and Goldreich \& {\bf Wu} (1999). Here, it is
applied to the different internal properties of gamma-Dors, which have
a stronger super-adiabatic gradient and a weaker convective flux than
white dwarfs. This leads to a spectrum of gravity-modes being excited
in the observed temperature range. This explanation for the pulsation
excitation is, however, still subject to uncertainties that need to be
resolved, e.g., the roles of fast rotation and convective overshoot.

\subsection{Early Universe}

Andrei {\bf Frolov} and Lev {\bf Kofman} studied the behavior of a light
cosmological scalar field (quintessence) in the strong gravitational
field near a black hole. An analytical approximation of the field
dynamics was developed and its accuracy confirmed by numerical
calculations. They found that the field profile is merely delayed, not
frozen, on the horizon, and that the long-range tails are formed
outside the horizon because of the stiffness of the light scalar
field. The rate of accretion of such fields by a black hole was
calculated.

Andrei {\bf Frolov} and Lev {\bf Kofman} are working on brane-world models of the
Universe. They developed a conformal transformation formalism that
significantly simplifies the study of brane and bulk geometry and
allows analytical treatment of a wide class of brane-world
solutions. In particular, the Randall-Sundrum model is reduced to a
flat manifold with empty boundaries. This formalism allows one to
construct exact brane-world solutions with induced brane-world metric
being an arbitrary Einstein spacetime. They also used this approach to
derive and solve gravitational perturbation equations for such
brane-world models. The normal four-dimensional gravitational waves
are recovered as the zero mode of decomposition, while the
higher-dimensional modes acquire effective 4D mass in a way similar to
Kaluza-Klein theory.

\subsection{Computational Astrophysics}

{\bf Arras}, {\bf Wu} and {\bf Pen} have developed an efficient numerical method to
compute fluid oscillations in rotating stars. This method makes a
limited number of approximations: (1) the background star has
negligible centrifugal flattening; (2) the perturbations are
adiabatic; (3) the Cowling approximation; and (4) the stellar rotation
is uniform. The linearized Euler and continuity equations are solved
including an external forcing term and a freely specified equation of
state. As a result, any ratio of Brunt-Vaisalla and rotation
frequencies is allowed, and compressibility effects are included. The
equations are differenced on a grid of radius and polar angle, since
the oscillation equations are not separable in these two
coordinates. The code can be used to find the fluid response for a
given external (e.g. tidal) forcing. In addition, {\bf Arras} et al. have
developed an efficient way of searching for eigenmodes using the
inverse power iteration method, requiring just a few iterations per
mode. A multigrid iteration scheme is under development (for a matrix
which is not diagonally dominant, symmetric, or positive definite),
which promises at least an order of magnitude better resolution.

In an ongoing project, {\bf Dubinski} Koranyi (Harvard) and Geller (Harvard)
have been studying the interactions of thousands of spiral galaxies in
cosmological N-body simulations of cluster formation to understand the
dynamics of clusters and the origins of the elliptical galaxies and
the fundamental plane relations.

{\bf Dubinski}, Kim (Seoul), Park (Seoul), and {\bf Humble} have developed a new
hybrid N-body code which combines the particle-mesh and treecode
algorithms. The code is parallelized and has been used to run
134-million-particle simulations of structure formation.

{\bf Dubinski} and summer student Aurelie Neveol have developed new software
for the visualization of N-body simulations. The new software
piggybacks on existing simulation software and produces image
sequences from static and dynamic cameras immersed within the
simulations producing exciting visual effects.  The software is being
used to produce High Definition Television animations of colliding
galaxies and dynamically evolving galaxy clusters for NHK Television
in Japan for an ongoing series in astronomy. {\bf Dubinski} is featured in
one program and discusses the fate of the Milky Way and Andromeda
galaxies.

{\bf Dubinski}, Brinkman (MPI) and Abraham (Toronto) are reviving the sticky
particle method to treat star formation in young galaxies. A subset of
particles are labelled as clouds and direct collisions are followed
and assumed to induce star formation with a given efficiency. The code
allows a detailed star formation history of a galaxy at high
resolution. The results of these models can be fed into observational
simulation software developed by Brinkman and Abraham for making
direct predictions about the morphology and brightness of galaxies in
different apertures.

Masters student O'Neill and {\bf Dubinski} are re-examining the formation of
bars in galactic disk and issues surrounding the buckling instability
and its connection to bulge formation as well as dynamical friction
drag on bars from the dark halo.

Garcia-Ruiz and Kuijken (Kapteyn) with {\bf Dubinski} have shown that the
warp of the Galaxy is not generated by direct tidal forcing or tidal
amplification from the galaxy halos as suggested by some
researchers. The source of the warp remains a puzzle.

Temperature profiles were determined by {\bf Loken} and collaborators
M. Norman and E. Nelson (UCSD), J. Burns (Missouri), A. Klypin
(N.M. State), G.L. Bryan (MIT) and P. Motl (Missouri) for two samples
of numerically-simulated galaxy clusters (in low density CDM and
standard CDM cosmologies) and it was shown that they agreed remarkably
well with the non-isothermal profiles claimed by Markevitch et
al. (1998) from their ASCA analysis.

Chris {\bf Loken} and collaborators P.L. Gomez (Carnegie-Mellon),
K. Roettiger (Missouri), and J.O. Burns have performed a series of 2D
simulations of the merger of a cooling flow cluster with an infalling
subcluster. They found that the ram-pressure of the infalling gas is
crucial in determining the fate of the cooling flow as disruption
occurs when a substantial amount of subcluster gas reaches the
primary's core. It was shown that, even in the case of disruption, a
cluster can be classifed as a cooling flow and also exhibit
substructure. The results make it possible to reconcile the high
cooling flow frequency inferred by some observations with both high
merger rates and a high frequency of substructure.

Chris {\bf Loken}, C.A. Metzler (CfA) and M. White (CfA) used large-scale
numerical simulations of structure formation in a lambda-dominated
cold dark matter model to quantify the effect that large-scale
structure near clusters has upon the cluster masses deduced from weak
lensing analysis. It was concluded that a correction for the scatter
in possible observed lensing masses should be included when
interpreting mass functions from weak lensing surveys.

{\bf Pen} and Trac (Toronto) are building a dedicated out-of-core machine,
funded by the Canada Foundation for Innovation, which has 10 Terabytes
of virtual memory with a bandwidth of 6 Gigabytes/second. This device
will be sufficient for direct cosmological simulations of gas and dark
matter on three-dimensional grids five thousand cells wide.


\begin{publications}

{\it The publication list includes all papers published or submitted
from September 2000 to August 2001 by the CITA staff, or by visitors 
if a substantial portion of the work was done at CITA.}


\reference Aburihan, M., Fiege, J.D., Henriksen, R. N., and Lery, T. 2001, MNRAS, 326, 1217 

\reference Arav, N., de Kool, M., Korista, K.T., Crenshaw, D.M., van Breugel, W., Brotherton, M., Green, R.F., Pettini, M., Wills, B., de Vries, W., Becker, B., Brandt,
     W.N., Green, P., Junkkarinen, V.T., Koratkar, A., Laor, A. Laurent-Muehleisen, S.A., Mathur, S., and Murray N., ApJ, submitted (astro-ph/0107414) 

\reference Athreya, R.M., Hoekstra, H., Mellier, Y., Cuillandre, J.-C., and Narasimha, D., 2001, in proceedings of Gravitational Lensing: Recent Progress and Future
     Goals, eds. T.G. Brainerd and C.S. Kochanek (ASP: San Francisco), p. 303 

\reference Bacon, R., Emsellem, E., Combes, F., Copin, Y., Monnet, G., and Martin, P. 2001, A\&A, 371, 409 

\reference Barkana, R. 2001, New Astronomy, in press (astro-ph/0108431)

\reference Barkana, R., Haiman, Z., and Ostriker, J.P. 2001, ApJ, 558, 482

\reference Barkana, R., Hogg, D.W., Loeb, A., and Blandford, R. 2001, in
proceedings of Gravitational Lensing: Recent Progress and Future Goals,
T.G. Brainerd and C.S. Kochanek (ASP: San Francisco), p. 413

\reference Beijersbergen, M., Hoekstra, H., van Dokkum, P.G., and van der Hulst, T. 2001, MNRAS, in press (astro-ph/0106354) 

\reference Beijersbergen, M., Hoekstra, H., van Dokkum, P.G., and van der Hulst, J.M. 2001, in proceedings of Gas and Galaxy Evolution eds. J.E. Hibbard, M. Rupen
     and J.. van Gorkom (ASP: San Francisco), p. 624 

\reference Bond, J.R., Pogosyan, D., and Prunet, S. 2001, Nuclear Physics B Proceedings Supplements, 91, 398-404, 

\reference Bond, J., and Crittenden, R. 2001, in proceedings NATO ASI ``Structure Formation in the Universe'', eds. R.G. Crittenden \& N.G. Turok (Kluwer) 2001 

\reference Bond, J.R., Pogosyan, D., Prunet, S., Ade, P., Balbi, A., Bock, J.,
     Borrill, J., Boscaleri, A., Coble, K., Crill, B., de Bernardis,
     P., Farese, P., Ferreira, P., Ganga, K., Giacometti, M., Hanany,
     S., Hivon, E., Hristov, V., Iacoangeli, A., Jaffe, A., Lange,
     A. Lee, A., Martinis, L., Masi, S., Mauskopf, P., Melchiorri, A.,
     Montroy, T., Netterfield, B., Oh, S., Pascale, E., Piacentini,
     F., Rabii, B., Rao, S., Richards, P., Romeo, G., Ruhl, J.,
     Scaramuzzi, F., Sforna, D., Smoot, G., Stompor, R., Winant, C.,
     Wu, P. in proceedings of Neutrino 2000 (Elsevier)
     (astro-ph/0011381)

\reference Bond, J.R., Pogosyan, D., Prunet, S., Sigurdson, K., Ade, P., Balbi,
     A., Bock, J., Borrill, J., Boscaleri, A., Coble, K., Crill, B.,
     de Bernardis, P. Farese, P., Ferreira, P., Ganga, K., Giacometti,
     M., Hanany, S., Hivon, E., Hristov, V., Iacoangeli, A., Jaffe,
     A., Lange, A., Lee, A., Martinis, L., Masi, S., Mauskopf, P.,
     Melchiorri, A., Montroy, T., Netterfield, B., Oh, S.,Pascale, E.,
     Piacentini, F., Rabii, B., Rao, S., Richards, P., Romeo, G.,
     Ruhl, J., Scaramuzzi, F., Sforna, D., Smoot, G., Stompor, R.,
     Winant, C., Wu, P. in proceedings of CAPP-2000 (AIP)
     (astro-ph/0011379)

\reference Bond, J.R., Ade, P., Balbi, A., Bock, J., Borrill, J., Boscaleri, A.,
     Coble, K., Crill, B., de Bernardis, P., Farese, P., Ferreira, P.,
     Ganga, K., Giacometti, M., Hanany, S., Hivon, E., Hristov, V.,
     Iacoangeli, A., Jaffe, A., Lange, A., Lee, A., Martinis, L.,
     Masi, S., Mauskopf, P., Melchiorri, A., Montroy, T., Netterfield,
     B., Oh, S., Pascale, E., Piacentini, F., Pogosyan, D., Prunet,
     S., Rabii, B., Rao, S., Richards, P., Romeo, G., Ruhl, J.,
     Scaramuzzi, F., Sforna, D., Sigurdson, K., Smoot, G., Stompor,
     R., Winant, C., Wu, P. in proceedings of IAU Symposium 201 (PASP)
     (astro-ph/0011378)

\reference Chen, L.-W., Ma, C.-P., Ng, K.-W., Pen, U.-L. 2001, in AMiBA 2001:
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     eds. L.-W. Chen, C.-P.  Ma, K.-W. Ng, and U.-L. Pen, (ASP: San
     Francisco)

\reference Colombi, S., Pogosyan, D., and Souradeep, T. 2000, Phys. Rev. Lett, 85, 5515 

\reference Contaldi, C.R., and Magueijo, J. 2001, Physical Review D, 63, 3512, 

\reference Crittenden, R.G., Natarajan, P., Pen, U.-L., and Theuns, T. 2001, ApJ,
559, 552

\reference Daddi, E., Cimatti, A., Pozzetti, L., Hoekstra, H., Rottgering, H.J.A., Renzini, A., Zamorani, G., and Mannucci, F. 2000, A\&A, 361, 535 

\reference  de Bernardis, P., Ade, P.A.R., Bock, J.J., Bond, J.R., Borrill, J.,
     Boscaleri, A., Coble, K., Crill, B.P., de Gasperis, G., de Troia,
     G. Farese, P.C., Ferreira, P.G., Ganga, K., Giacometti, M.,
     Hivon, E., Hristov, V.V., Iacoangeli, A., Jaffe, A.H., Lange,
     A.E., Martinis, L. Masi, S., Mason, P., Mauskopf, P.D.,
     Melchiorri, A., Miglio, L., Montroy, T., Netterfield, C.B.,
     Pascale, E., Piacentini, F., Pogosyan, D., Pongetti, F., Prunet,
     S., Rao, S., Romeo, G., Ruhl, J.E., Scaramuzzi, F., Sforna, D.,
     Vittorio, N. 2000, in proceedings of IAU Symposium 201: `New
     Cosmological Data and the Values of the Fundamental Parameters',
     Manchester, 7-11 Aug. 2000 (astro-ph/0011468)

\reference de Bernardis, P., Ade, P.A.R., Bock, J.J., Bond, J.R., Borrill, J.,
     Boscaleri, A., Coble, K., Crill, B.P., De Gasperis, G., De Troia,
     G., Farese, P.C., Ferreira, P.G., Ganga, K., Giacometti, M.,
     Hivon, E., Hristov, V.V., Iacoangeli, A., Jaffe, A.H., Lange,
     A.E., Martinis, L. Masi, S., Mason, P., Mauskopf, P.D.,
     Melchiorri, A., Miglio, L., Montroy, T., Netterfield, C.B.,
     Pascale, E., Piacentini, F., Pogosyan, D., Pongetti, F., Prunet,
     S., Rao, S., Romeo, G., Ruhl, J.E., Scaramuzzi, F., Sforna, D.,
     Vittorio, N. 2000, in proceedings of the CAPP2000 conference,
     Verbier, 17-28 July 2000 (astro-ph/0011469)

\reference de Bernardis, P. Ade, P.A.R., Bock, J.J., Bond, J.R., Boscareli, A.,
     Coble, K., Contaldi, C.R., Crill, B.P., de Troia, G., Farese, P.,
     Ganga, K., Giacometti, M., Hivon, E., Hristov, V.V., Iacoangeli,
     A., Jaffe, A.H., Jones, W.C., Lange, A.E., Martinis, L., Masi,
     S., Mason, P., Mauskopf, P.D., Melchiorri, A., Montroy, T.,
     Pascale, E., Piacentini, F., Pogosyan, D., Polenta, G. Pongetti,
     F., Prunet, S., Romeo, G., Ruhl, J.E., and Scaramuzzi F., ApJ, in
     press (astro-ph/0105296)

\reference Dore, O., Teyssier, R., Bouchet, F.R., Vibert, D., and Prunet, S. 2001, A\&A, 374, 358 

\reference Felder, G., and Tkachev, I. 2000, hep-ph/0011159 LATTICEEASY: A Program for Lattice Simulations of Scalar Fields in an Expanding Universe 

\reference Felder, G., and Kofman, L. 2001, Physical Review D, 63, 3503 

\reference Felder, G., Kofman, L. and Linde, A. 2001, Physical Review D, 64, 123517 

\reference 
Felder, G., Garcia-Bellido, J., Greene, P.B., Kofman, L., Linde, A., and Tkachev, I. 2001, Physical Review Letters, 87, 1601, 

\reference Feroci, M.; Hurley, K.; Duncan, R. C.; Thompson, C 2001ApJ...549.1021F 

\reference Fiege, J.D. and Pudritz, R.E. 2000, ApJ, 544, 830 

\reference Fox, D. and Pen, U.-L. 2001, ApJ, 546, 35 

\reference Franx, M., Hoekstra, H., and Kuijken, K. 2001, in proceedings of Gravitational Lensing: Recent Progress and Future Goals, eds. T.G. Brainerd and C.S.
     Kochanek (ASP: San Francisco), p. 287 

\reference Frolov, A.V. 2001, Physics Letters B, 514, 213-216, 

\reference Garcia-Ruiz, I., Kuijken, K. and Dubinski J. 2002, MNRAS, in press Galactic Warps 

\reference Gogus, E., Kouveliotou, C., Woods, P.M., Thompson, C., Duncan, R.C., Briggs, M.S. 2001, ApJ, 558, 228 

\reference Gomez, P., Loken, C., Roettiger, K., Burns, J. 2001, ApJ, in press (astro-ph/0009465) 

\reference Greene, P.B., and Kofman, L. 2000, Physical Review D, 62, 3516, 

\reference Haarsma, D., Lehar, J., and Barkana, R. 2001, in
proceedings of Gravitational Lensing: Recent Progress and Future Goals,
T.G. Brainerd and C.S. Kochanek (ASP: San Francisco), p. 89

\reference Haiman, Z., Barkana, R., and Ostriker, J.P. 2001, in proceedings
of the 20th Texas Symposium on Relativistic Astrophysics, ed. 
J.C. Wheeler and H. Martel, (AIP: New York)

\reference Hansen, B.M.S., and Lyutikov, M. 2001, MNRAS, 322, 695 

\reference Heyl, J.S. and Shaviv, N. 2001, Phys. Rev. Lett., submitted 

\reference Hoekstra, H. 2001, A\&A, 370, 743-753, 

\reference Hoekstra, H., Franx, M., Kuijken, K., Carlberg, R. G., Yee, H.K.C., Lin, H., Morris, S.L., Hall, P.B., Patton, D.R., Sawicki, M., and Wirth, G.D. 2001, ApJL,
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\reference Hoekstra, H., Yee, H.K.C., and Gladders, M.D. 2001, ApJ, 558, L1 

\reference Hoekstra, H., van Albada, T.S., and Sancisi, R. 2001, MNRAS, 323, 453 

\reference Hoekstra, H., Yee, H., and Gladders, M. 2001, in the proceedings of the STScI 2001 spring symposium "Dark Universe" (astro-ph/0106388) 

\reference Hoekstra, H., Franx, M., Kuijken, K, and van Dokkum, P. 2001, submitted to MNRAS (astro-ph/0109445) 

\reference 
Hoekstra, H., Yee, H., and Gladders, M. 2001, proceedings for "Where's the matter?", Marseille (astro-ph/0109514) 

\reference Hoyle, F., Szapudi, I., and Baugh, C.M. 2000, MNRAS, 317, L51 

\reference Ibrahim, A.I., Strohmayer, T.E., Woods, P.M., Kouveliotou, C., Thompson, C., Duncan, R.C., Dieters, S., Swank, J.H., van Paradijs, J., Finger, M. 2001, ApJ,
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\reference Jaffe, A.H., Ade, P.A.R., Balbi, A., Bock, J.J., Bond, J.R., Borrill,
     J., Boscaleri, A., Coble, K., Crill, B.P., de Bernardis, P.,
     Farese, P., Ferreira, P.G., Ganga, K., Giacometti, M., Hanany,
     S., Hivon, E., Hristov, V.V., Iacoangeli, A., Lange, A.E., Lee,
     A.T., Martinis, L., Masi, S., Mauskopf P.D., Melchiorri, A.,
     Montroy, T., Netterfield, C.B., Oh, S., Pascale, E., Piacentini,
     F., Pogosyan, D., Prunet, S., Rabii, B., Rao, S., Richards, P.L.,
     Romeo, G., Ruhl, J.E., Scaramuzzi, F., Sforna, D., Smoot, G.F.,
     Stompor, R., Winant, C.D., and Wu J.H.P. 2001, Phys. Rev. Lett.,
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\reference Jones, C.E., Basu, S., and Dubinski, J. 2001, ApJ, 551, 387-393, 

\reference  Kallosh, R., Kofman, L., Linde, A., and Tseytlin, A. 2001, PRD, submitted (hep-th/0106241) 

\reference Kallosh, R., Kofman, L., and Linde, A. 2001, preprint (hep-th/0104073) 

\reference Kerton, C.R., and Martin, P.G. 2001, PASP, 113, 872 

\reference Kerton, C.R., Martin, P.G., Johnstone, D., and Ballantyne, D. R. 2001, ApJ, 552, 601-613, 

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\end{publications}

\end{document}










\leftline{}
The research focus of the Associates and Faculty are as follows, sorted by
topic:

 \leftline{}
{\centerline \bf Cosmology} 


\par\hangindent=10pt\hangafter=1 $\bullet$~{\bf Rennan {\bf Barkana} works
on theoretical modeling of the first generation of galaxies and the
reionization of the universe. Early on, the universe was dense and
hot. At a cosmic age of 400,000 years, the expanding universe cooled
enough that hydrogen atoms formed out of electrons and protons. Based
on theoretical models, the first galaxies are thought to have formed
when the universe was 100-200 million years old. These sources emitted
ionizing radiation, and began to reionize some of the hydrogen in the
universe. This reionization process was an important phase transition,
where the gas throughout the universe went from being cold and neutral
to warm and ionized. Upcoming observations are expected to probe this
era in cosmic history.

\par\hangindent=10pt\hangafter=1 $\bullet$~{\bf J. Richard Bond}, 
CITA's Director, works on theoretical
problems ranging from the physics of the early universe (in
particular, inflation theory), cosmic background radiation, nonlinear
evolution of cosmic structure (the cosmic web approach to
hydrodynamical simulations, galaxy formation, Lyman alpha clouds,
and supercluster formation and evolution), as well as analysis methods for
confronting cosmological theories with large cosmological
databases. Most recently, he has been heavily involved in the
interpretation of data from the BOOMERanG balloon-borne experiment,
which measured the cosmic microwave background in unprecedented
detail.

\par\hangindent=10pt\hangafter=1 $\bullet$~{\bf Carlo Contaldi} works
on the calculation of cosmological parameters from a number of Cosmic
Microwave Background data sets. During the past year he worked on a
new fast analysis pipeline for the BOOMERANG balloon borne experiment
which yielded the most accurate measurement of the CMB power spectrum
to date. He is also working on the interpretation of interferometric
data from Caltech's Cosmic Background Imager (CBI) which will provide
a measurement of the CMB power spectrum at extremely high angular
resolution (there are currently no measurement in this
range). Finally, he is working on effects relating to Non-Gaussianity
in the CMB; and on the use of weak lensing surveys to constrain the
origin of the dark energy which may be responsible for the observed
acceleration in the expansion of the Universe.


\par\hangindent=10pt\hangafter=1 $\bullet$~{\bf Henk Hoekstra} studies
the distribution of dark matter in the universe through its weak
gravitational lensing effect. The lensing signal induced by large
scale structure can be used to constrain cosmological parameters,
whereas the signal around galaxies provides a unique way to study
their dark matter halos. An exciting new application is the study of
galaxy biasing (the relation between mass and the light) which
provides important information about galaxy formation.  Most of the
current work is done in collaboration with H.K.C. Yee and
M.D. Gladders, and is based on the Red-Sequence Cluster Survey.

\par\hangindent=10pt\hangafter=1 $\bullet$~{\bf Ue-Li Pen} works on
problems in theoretical cosmology. Current interests include the
alignment of galaxies, large scale simulations and analysis of large
data sets.  Simulations are performed using the supercomputers at CITA
supported by the Canada Foundation for Innovation. Current research
focusses on the intergalactic medium, its history, evolution, current
state, and observational strategies to detect it.

\par\hangindent=10pt\hangafter=1 $\bullet$~{\bf 
Dmitri Pogosyan} works on the problems ranging from the theory of the early Universe and generation of initial cosmological perturbations, to Cosmic Microwave
Background theory and analysis, to the modeling of the observed Large-Scale Structure in the Universe and tests on cosmological models, to the observables of
galaxy clusters and intracluster structure as well as structures in the interstellar medium.
 

\par\hangindent=10pt\hangafter=1 $\bullet$~{\bf Istv\'an Szapudi} has
been studying higher order statistics in galaxy catalogs, such as the
Sloan Digital Sky Survey (SDSS). Statistical properties of large scale
structure are represented primarily through the distribution of
galaxies, but the underlying dark matter, which appears to dominate
the matter content of the universe, might have an entirely different
distribution. This phenomenon, ``bias'', has central role in modern
cosmology. Its understanding potentially constrains the nature and
distribution of dark matter, one of the most interesting issues of
21st century physics. Yet, at present, it constitutes the weakest link
in our theories of structure formation. Higher order statistics sheds
new light on these phenomena, and new measurements will translate into
tight constraints on the nature and distribution of the dark matter,
on Gaussianity of the initial conditions, and on the physics of galaxy
formation. Istvan Szapudi has been developing a suite of new methods
and algorithms for spatial statistical analyses of future large
astronomical data bases, such as galaxy catalogs (SDSS), megapixel CMB
maps (e.g., MAP and Planck). Contemporary data analysis tools are
inadequate for future large data sets, even with the most powerful
supercomputers existing or projected. As an example, standard analysis
of megapixel CMB maps from Planck would take a million years on
hypothetical computers equipped with TeraBytes of memory. The new
analysis suite created by Szapudi and collaborators, SpICE (Spatially
Inhomogeneous Correlation Estimator,
http://www.ifa.hawaii.edu/users/szapudi/istvan.html, click on AISR)
brings an order of billion fold improvement, enabling the analysis of
MAP and Planck in less then 5 and 40 minutes, respectively. In
addition to megapixel CMB maps, the novel methods developed in this
research will be immensely useful for joint analysis of future surveys
across several wavelengths, as envisioned in the planned National
Virtual Observatory (NVO) framework.


\par\hangindent=10pt\hangafter=1 $\bullet$~{\bf Ludovic Van Waerbeke}
works on observational and theoretical problems related to
gravitational lensing by large scale structures, and its impact on the
measurement of cosmological parameters and on the distribution of dark
matter. He measured on different data sets the lensing effect induced
by foreground galaxies (mean redshift 0.4) on background galaxies
(mean redshift 0.9) and defined news analysis tools usefull to
separate signal and residual systematics. From these data, he obtained
the first comoslogical parameters constraints from cosmic shear
measurements and the first mass power spectrum estimation. On the
theoretical side, he worked on the prediction of the non-linear signal
induced by the non-linear clustering of matter (using ray-tracing
simulations and semi-analytic tools). He also studied the statistics
of dark matter halos, expected in lensing surveys.


\leftline{}
{\centerline \bf Galaxies and Dynamics} 

\par\hangindent=10pt\hangafter=1 $\bullet$~{\bf John Dubinski} works
on problems relating to galaxy formation and galaxy dynamics. He is
studying galaxy dynamical evolution in a cosmological context, using
N-body simulation to understand the origin of the elliptical galaxies
and their scaling properties. He also is developing new parallel
N-body code for studies of cosmology, galaxy dynamics and planet
formation. 

\par\hangindent=10pt\hangafter=1 $\bullet$~{\bf Robin Humble} works on
planet formation using a dusty self gravitating protoplanetary disk
model. Dust is followed as it collapses in gravitationally unstable
regions and accretes into larger bodies. Full Navier-Stokes equations
with two fluid phases (dust and gas) are solved. Progress is also
being made on the addition of fluid dynamics to a large cosmological
N-body code.

 \leftline{}
{\centerline \bf Interstellar Medium} 

\par\hangindent=10pt\hangafter=1 $\bullet$~{\bf Jason Fiege} works on
problems related to star formation and the structure of magnetic
fields in star-forming molecular clouds. He is currently developing
detailed models of the sub-millimetre polarization patterns observed
in molecular clouds, to test theoretical models of the magnetic fields
in these regions.  He is also working the the support of molecular
clouds by Alfv\'enic turbulence, and developing a self-similar model
for the anisotropic collapse of pre-protostellar cores and the
formation of bipolar outflows in these regions.

\par\hangindent=10pt\hangafter=1 $\bullet$~{\bf Peter
van Hoof} studies the late stages of evolution of intermediate mass
stars, i.e. post-Asymptotic Giant Branch (post-AGB) stars and
planetary nebulae (PNe), and their outflows. The long-term goals of
this research are to obtain a large sample of post-AGB stars and PNe,
and use this to test stellar evolution models, study mass loss
processes, and deepen our understanding of grain formation and
evolution. He has completely rewritten the grain model in the
photo-ionization code Cloudy. It now incorporates a Mie code, is able
to resolve the grain size distribution, and can treat non-equilibrium
heating of grains. It is currently being used to model the grain
emission in the Orion nebula.


\par\hangindent=10pt\hangafter=1 $\bullet$~{\bf Peter Martin} is
engaged in studies of interstellar matter and its relationship to
stellar evolution (the birth of stars and planets, nucleosynthesis of
the elements in stars, and the death of stars). Although it appears
that humanity derives ultimately from diffuse dust and gas in the
interstellar medium (ISM) in the Milky Way, many details are still
shrouded in the mysteries of the Galactic ecosystem, where
counterbalancing, often violent, forces have shaped the ISM and star
formation within it over the eons. Consequently, his research includes
theoretical work understanding basic physical processes, incorporating
them in astrophysical simulations, and analysis and interpretation of
strategically-acquired multifrequency data from ground- and
space-based telescopes. Themes within the context of the Galactic
ecosystem include the evolution of interstellar grains; chemical
abundances and nebular structure; molecular hydrogen near regions of
star formation; clouds and turbulence; interstellar polarization.


\par\hangindent=10pt\hangafter=1 $\bullet$~{\bf Joseph
Weingartner} works on problems related to the interstellar
medium. With collaborators at Princeton, he has developed a detailed
interstellar dust model that reproduces the observed extinction of
starlight and dust emission. He also studies physical processes
involving interstellar grains, particularly their interaction with
starlight and with the interstellar gas. Finally, he is working on
elucidating the physical mechanism whereby nonspherical grains become
aligned with the interstellar magnetic field. An improved
understanding of the alignment process should help astronomers to use
polarized emission from grains as a diagnostic of the magnetic field.


 \leftline{}
{\centerline \bf High-Energy Astrophysics and Compact Objects} 

\par\hangindent=10pt\hangafter=1 $\bullet$~{\bf Phil Arras}
focuses on a variety of problems in stellar hydrodynamics. Arras
studies the nonlinear saturation of the Rossby wave (R-mode) instability in
rapidly
rotating neutron stars, which is a promising mechanism to set the
observed spins of neutron stars, as well as possibly being a source of
gravitational radiation. He has developed a novel numerical method for
solving the two-dimensional partial differential equations for the
eigenmodes of rapidly rotating stars with both high accuracy and
speed. He is studying the dynamical tide in Jupiter due to forcing
from its moons, and the resultant tidal Q. Another application is the
contribution of the dynamical tide to the circularization of low mass
main sequence binaries. Arras' other interests include the evolution
of magnetic fields in white dwarfs and neutron stars, protoneutron
star neutrino transport and convection, and pulsar kicks.


\par\hangindent=10pt\hangafter=1 $\bullet$~{\bf Maxim Lyutikov} works
on pulsars (radio emission generation, wave propagation inside
magnetosphere, pulsar winds), gamma-ray bursts, planetary dynamics,
turbulence.

\par\hangindent=10pt\hangafter=1 $\bullet$~{\bf Christopher Matzner}
studies problems related to the birth and death of stars. In the field
of star formation, his work concerns several mechanisms by which
newborn stars interact with the clouds from which they form:
protostellar winds, ionization nebulae, and supernova explosions, and
the implications of these interactions for the nature and evolution of
star-forming clouds. Matzner also studies the possible link between
supernova explosions and gamma-ray bursts (GRBs); there, his work
includes models for the production of weak GRBs by relativistic shock
acceleration, as well as the dynamics of relativistic jets emerging
from stellar envelopes. He is also investigating the kicks that neutron stars
apparently receive at birth. 

\par\hangindent=10pt\hangafter=1 $\bullet$~{\bf Mikhail Medvedev}
works in various fields of theoretical astrophysics. (I) He studies
hot accretion onto compact objects such as black holes, neutron stars
and white dwarfs. This problem is crucial to reveal the nature of
primaries in X-ray/gamma-ray emitting close binary systems and
supermassive black holes in AGNs, to understand the physics of
outflows in micro- and normal quasars, to test general relativity in
the high-field limit, and much more. These studies are at the frontier
of observational astrophysics, thanks to Chandra, XMM, BSAX and other
missions. (II) He works on the problem of gamma-ray bursts (GRBs).
Studying the fireball properties will shed some light onto the nature
of this extremely violent phenomenon, as well as into the physics of
other cosmic explosions.  (III) He develops a phenomenological model
of dark matter, the the nature and properties of which remain one of
the greatest mysteries. (IV) He works on the explanation of the
absence rapid mass drop-out in cooling flows in galaxy clusters. The
absence of large-scale clouds of cold gas revealed with Chandra and
XMM contradicts our current understanding of the dynamics of cooling
flows. (V) Other topics of interest are the structure and dynamics of
self-gravitating systems (such as molecular clouds, galaxies,
clusters, etc.), hydrodynamic, MHD and Alfvenic turbulence, nonlinear
waves, transport phenomena in gases and plasmas, various aspects of
statistical and quantum physics, etc.

\par\hangindent=10pt\hangafter=1 $\bullet$~{\bf Norm Murray} carries
out research on a variety of topics, including planet formation,
radiative outflows in quasars and other objects, the physics of black
holes and neutron stars, and stellar physics.


\par\hangindent=10pt\hangafter=1 $\bullet$~{\bf Nir Shaviv} currently
works on a range of problems, from compact objects and stellar physics
to galactic dynamics and its terrestrial effects. In the field of
compact objects, he has been concentrating on various QED and plasma
effects that the magnetized vacuum and magnetospheric plasma have on
the propagation of photons. In the realm of stellar physics, he has
been studying amongst various topics, the behavior of luminous
atmospheres shining close to and above the Eddington limit and their
application to various objects, such as classical nova
eruptions. Last, he has also been interested in the Milky Way
dynamics, cosmic ray propagation and climate on Earth, which were all
found to be related.


\par\hangindent=10pt\hangafter=1 $\bullet$~{\bf Christopher Thompson}
works on problems in high energy astrophysics, radiative physics,
supernova core collapse, and relativistic fluids.



\par\hangindent=10pt\hangafter=1 $\bullet$~{\bf Yanqin Wu} works in
two broad areas: stellar hydrodynamics and the formation and evolution
of planets. She investigates processes including convection, rotation,
pulsation, mode coupling, dynamo, tidal interaction, and gravitational
dynamics, to answer questions raised by observations, e.g., what
excites and saturates stellar oscillations? how to understand the
pulsation power spectrum of fast rotating stars? what causes tidal
energy dissipation in a binary systems? what leads to the high 'kick'
velocity a neutron star received at its birth? how does angular
momentum evolve in stars? how to explain the observed eccentricities
of extra-solar planets? how do these planets migrate inward toward the
host star and when?

\leftline{}
{\centerline \bf The Early Universe}


\par\hangindent=10pt\hangafter=1 $\bullet$~{\bf Andrei Frolov } works
on problems in general relativity and theoretical cosmology. His
recent topic of interest is brane-world models of the Universe, in
which our four-dimensional world is a surface (brane) embedded in a
higher dimensional bulk spacetime, and their observable
consequences. His other research interests include the early Universe,
exact solutions of general relativity, and black hole physics.



\par\hangindent=10pt\hangafter=1 $\bullet$~{\bf Lev Kofman} works
primarily on cosmology, including physics of the very early universe
and the large scale structure
