A search for cosmic microwave background anisotropies on arcminute scales with bolocam

Abstract

We have surveyed two science fields totaling 1 deg2 with Bolocam at 2.1 mm to search for secondary Cosmic Microwave Background (CMB) anisotropies caused by the Sunyaev-Zel'dovich effect (SZE). The fields are in the Lynx and Subaru/XMM SDS1 fields. Our survey is sensitive to angular scales with an effective angular multipole of ℓeff = 5700 with FWHM ℓ = 2800 and has an angular resolution of 60 arcsec FWHM. Our data provide no evidence for anisotropy. We are able to constrain the level of total astronomical anisotropy, modeled as a flat-band power in , with most frequent 68%, 90%, and 95% CL upper limits of 590, 760, and 830 μK 2CMB. We statistically subtract the known contribution from primary CMB anisotropy, including cosmic variance, to obtain constraints on the SZE anisotropy contribution. Now including flux calibration uncertainty, our most frequent 68%, 90%, and 95% CL upper limits on a flat-band power in are 690, 960, and 1000 μK 2CMB. When we instead employ the analytical spectrum suggested by Komatsu and Seljack in 2002, and account for the non-Gaussianity of the SZE anisotropy signal, we obtain upper limits on the average amplitude of their spectrum weighted by our transfer function of 790, 1060, and 1080 μK 2CMB. We obtain a 90% CL upper limit on σ8, which normalizes the power spectrum of density fluctuations, of 1.57. These are the first constraints on anisotropy and σ8 from survey data at these angular scales at frequencies near 150 GHz. © 2009. The American Astronomical Society. All rights reserved.