ALMA Day

CITA and DI are hosting Atacama Large Millimeter Array day (ALMA) on Monday  March 17, 2014. There will be
visitors coming from  March 13th to March 19th 2014. A few ALMA-related seminars will be given on Monday.

Organizer: Quang Nguyen Luong

All seminars are open for CITA/DI and public in MP1318.

Monday 17 March 2014
11.00 – 12.00    ALMA observatory (Tracey Hill, ALMA Chile)
Lunch
14.10 – 15.00   First ALMA views of H2D+ and small-scale structure toward
clustered star-forming cores  (Rachel Friesen, Dunlap)
Coffee
15.10 – 16.00    From cloud structure to star formation (CEA, France)

ALMA observatory (Tracey Hill, ALMA Chile)

Abstract: ALMA has been partially operated since 2001 and will be soon
fully operated. I will describe the ALMA observatory. its operation and
science.

First ALMA views of H2D+ and small-scale structure toward clustered star-forming cores (Rachel Friesen, Dunlap)
Abstract: Since most stars in our galaxy form in clusters, understanding clustered
star formation has become a key goal of star formation astronomy. The
transition from prestellar core to first hydrostatic core (FHSC) or
protostar, while clearly a vital step in the process of star formation,
has not been well studied observationally due to the short lifetime of
the FHSC stage, difficulties in establishing the relative evolutionary
stage of objects, the small spatial scales involved, and the dearth of
strong molecular tracers of cores at high densities. We present Atacama
Large Millimeter/submillimeter Array observations of the submillimeter
dust continuum and H2D+ toward two evolved, potentially protostellar
cores within the Ophiuchus molecular cloud, OphA-SM1 and SM1N. The data
reveal singular small-scale condensations within both cores, with
effective radii ~ 40 AU and 400 AU, and maximum masses M < 0.02 MSun. We
find no evidence for substructure in either source, and a Jeans analysis
indicates they are unlikely to thermally fragment, suggesting both cores
will form single stars. These data reveal observationally the earliest
stages of the formation of circumstellar accretion regions, and indicate
disk formation can occur very early in the star formation process,
coeval with or just post the formation of a first hydrostatic core or
protostar.

From cloud structure to star formation (Motte, CEA, France)

Abstract: Massive stars are the main agent to the physical, chemical and dynamic
evolution of galaxies. But how they form is not yet understood. To
understand the mechamisms leading to their formation it is crucial to
observe them in their very earliest stage of evolution and to
characterize their physical properties (density, mass, temperature,
luminosity) and to obtain a global view of the cloud where they are
forming. It is in this framework that the program Herschel HOBYS (P.I.
F. Motte, A. Zavagno, S. Bontemps) has led a census and a systematic
study of massive dense cores into nearby (Distance < 3 kpc) star-forming
regions based on PACS et SPIRE images made in the five Herschel bandes
(70, 160, 250, 350 et 500 microns). The first results obtained by the
HOBYS consortium show a strong link between the position of the dense
cores and the interstellar filaments. The low mass cores seems to be
located along the filaments while the massive proto-stellar clusters
appear to form preferentially at the filamentary junctions (ridges). In
parrallel, the HII region impact to the star-formation is still to
explore. A natural follow up of the massive dense cores in early phase,
put in evidence thanks to Herschel is to observe them at high-angular
resolution with ALMA/NOEMA in order to characterise their possible
fragmentation, to study their chemistry and their kinematics.

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