Arcminute Cosmology Bolometer Array Receiver

ACBAR Publications

High Resolution Observations of the CMB Power Spectrum with ACBAR
C.L. Kuo, P.A.R. Ade, J.J. Bock, C. Cantalupo, M.D. Daub, J. Goldstein, W.L. Holzapfel , A.E. Lange, M. Lueker, M. Newcomb, J.B. Peterson, J. Ruhl, M.C. Runyan, E. Torbet

We report the first measurements of anisotropy in the cosmic microwave background (CMB) radiation with the Arcminute Cosmology Bolometer Array Receiver ACBAR. The instrument was installed on the 2.1m Viper telescope at the South Pole in January 2001; the data presented here are the product of observations up to and including July 2002. The two deep fields presented here, have had offsets removed by subtracting lead and trail observations and cover approximately 24 deg^2 of sky selected for low dust contrast. These results represent the highest signal to noise observations of CMB anisotropy to date; in the deepest 150 GHz band map, we reached an RMS of 8.0 uK per 5' beam. The 3 degree extent of the maps, and small beamsize of the experiment allow the measurement of the CMB anisotropy power spectrum over the range $\ell = 150-3000$ with resolution of $\Delta \ell=150$. The contributions of galactic dust and radio sources to the observed anisotropy are negligible and are removed in the analysis. The resulting power spectrum is found to be consistent with the primary anisotropy expected in a concordance $\Lambda$CDM Universe.

Postscript preprint of the paper (3.6 MB). Also available at astro-ph/0212289.

Estimates of Cosmological Parameters Using the CMB Angular Power Spectrum of ACBAR
J. H. Goldstein, P. A. R. Ade, J. J. Bock, J. R. Bond, C. Cantalupo, C. R. Contaldi, M. D. Daub, W. L. Holzapfel, C. Kuo, A. E. Lange, M. Lueker, M. Newcomb, J. B. Peterson, D. Pogosyan, J. E. Ruhl, M. C. Runyan, E. Torbet

We report an investigation of cosmological parameters based on the measurements of anisotropy in the cosmic microwave background radiation (CMB) made by ACBAR. We use the ACBAR data in concert with other recent CMB measurements to derive Bayesian estimates of parameters in inflation-motivated adiabatic cold dark matter models. We apply a series of additional cosmological constraints on the shape and amplitude of the density power spectrum, the Hubble parameter and from supernovae to further refine our parameter estimates. Previous estimates of parameters are confirmed, with sensitive measurements of the power spectrum now ranging from \ell \sim 3 to 2800. Comparing individual best model fits, we find that the addition of \Omega_\Lambda as a parameter dramatically improves the fits. We also use the high-\ell data of ACBAR, along with similar data from CBI and BIMA, to investigate potential secondary anisotropies from the Sunyaev-Zeldovich effect. We show that the results from the three experiments are consistent under this interpretation, and use the data, combined and individually, to estimate \sigma_8 from the Sunyaev-Zeldovich component.

A preprint is availible at: astro-ph/0212517

The Arcminute Cosmology Bolometer Array Receiver
M.C. Runyan, P.A.R. Ade, R.S. Bhatia, J.J. Bock, M.D. Daub, J.H. Goldstein, C.V. Haynes, W.L. Holzapfel, C.L. Kuo, A.E. Lange, J. Leong, M. Lueker, M. Newcomb, J.B. Peterson, J. Ruhl, G. Sirbi, E. Torbet, C. Tucker, A.D. Turner, D. Woolsey

We describe the Arcminute Cosmology Bolometer Array Receiver (ACBAR); a multifrequency millimeter-wave receiver designed for observations of the Cosmic Microwave Background (CMB) and the Sunyaev-Zel'dovich effect in clusters of galaxies. The ACBAR focal plane consists of a 16-pixel, background-limited, 240 mK bolometer array that can be configured to observe simultaneously at 150, 220, 280, and 350 GHz. With 4-5' FWHM Gaussian beam sizes and a 3 degree azimuth chop, ACBAR is sensitive to a wide range of angular scales. ACBAR was installed on the 2 m Viper telescope at the South Pole in January 2001. We describe the design of the instrument and its performance during the 2001 and 2002 observing seasons.

A preprint is availible at: astro-ph/0303515