Dick Bond

Research Summary

[ Computational Astrophysics, Cosmology, Early Universe ]

Dick Bond works on the theory of tiny cosmic microwave background (CMB) fluctations, geometrical mappings of sound waves when this "oldest light in the Universe" decoupled from matter some 14 gigayears ago. These fluctuations encode information on the many parameters that define cosmic structure formation theory, which he and collaborators determine by analysis of data from Boomerang, CBI and other CMB experiments. The impact this has on inflation and the early universe is of great interest to him, as is the nature and behaviour of dark matter and dark energy. Another area of active research is the "cosmic web" paradigm for structure formation from the nonlinear dynamics of random density fields. He is studying the distribution and state of gas in the Universe that this engenders, through gasdynamical studies of the intergalactic medium at high redshift (Lyman alpha forest) and the intercluster/intracluster medium at lower redshift (the Sunyaev-Zeldovich effect).

Research Projects:
(September 2002 - August 2003)

Analysis of Cosmic Background Interferometer CMB Data

CITA researchers Dick Bond, Carlo Contaldi, and Ue-Li Pen collaborated with former CITAzens Dmitry Pogosyan (University of Alberta), Steve Myers (NRAO), and Simon Prunet(IAP) and with Brian Mason (NRAO) and Tim Pearson, Tony Readhead and Jonathon Sievers of Caltech (now at CITA) to analyze new measurements of the polarization of the CMB from the Cosmic Background Imager experiment, a 13 element interferometer sited on the Atacama plateau in Chile. The work involved the extension of the analysis pipleline developed by the collaboration to include polarization of the CMB. The CBI aims to be the first instrument to return results on the polarization spectrum at arcminute scales. The first results covering the analysis of the first year of polarization measurements are expected to be released in early 2004. As part of the collaboration Dick Bond, Carlo Contaldi, and Ue-Li Pen have also been completing the analysis of the previously collected CBI total intensity measurements extending the analysis to two full years of data. This work follows on from the ground breaking results announced in May 2002 in a series of five papers by the CBI collaboration.

Analysis of Boomerang CMB Data

The Boomerang team members at CITA, Dick Bond, Carlo Contaldi and Barth Netterfield concluded the analysis of the 1998 flight data in a paper where the analyzed area was extended to cover roughly 3% of the sky. The work highlighted the robustness of the measurements and presented the definitive picture of the power spectrum at multipoles l<1000. The Boomerang effort has now shifted to the analysis of the latest flight (January 2003) which featured Polarization Sensitive Bolometers (PSB) for the measurement of polarization of the CMB. This work is ongoing and intense and is expected to produce a spectrum of the polarization in early 2004. The target is to map the first acoustic pea in the "E"-type (gradient) polarization, giving further confirmation of the basic paradigm of perturbation generation but also revealing the details of recombination and possible deviations from the standard picture of anisotropy formation.

Analysis of ACBAR data

Dick Bond and Carlo contaldi, together with Dmitry Pogosyan (University of Alberta) collaborated with the ACBAR experiment (PI Bill Holzapfel, UC Berkeley) in the analysis of the ACBAR data. The ACBAR team published a power spectrum with higly accurately determined band powers in the range of multipoles between 1000 and 2500. The work focused on extracting parameter constraints using the ACBAR spectrum and other measurements. The results were publihsed in a paper (Goldstein et al.) that defined the final snap-shot of the state of the field immediately previous to the realease of the first WMAP results. When compared to the WMAP results it highlights how successfully and accurately the CMB experiments leading upto the WMAP release had mapped out the basic features of the spectrum upto l=1000.

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