CONSTRAINTS ON THE HIGH-ℓ POWER SPECTRUM OF MILLIMETER-WAVE ANISOTROPIES FROM APEX-SZ

Abstract

We present measurements of the angular power spectrum of millimeter wave anisotropies with the APEX-SZ instrument. APEX-SZ has mapped 0.8 deg(2) of sky at a frequency of 150 GHz with an angular resolution of 1('). These new measurements significantly improve the constraints on anisotropy power at 150 GHz over the range of angular multipoles 3000 < l < 10, 000, limiting the total astronomical signal in a flat band power to be less than 105 μK(2) at 95% CL. We expect both submillimeter-bright, dusty galaxies and to a lesser extent secondary cosmic microwave background anisotropies from the Sunyaev-Zel'dovich effect (SZE) to significantly contribute to the observed power. Subtracting the SZE power spectrum expected for σ(8) = 0.8 and masking bright sources, the best-fit value for the remaining power is C( l) = 1.1(+0.9) (–0.8) × 10(–5) μK(2) (1.7(+1.4)( –1.3) Jy(2) sr(–1)). This agrees well with model predictions for power due to submillimeter-bright, dusty galaxies. Comparing this power to the power detected by BLAST at 600 GHz, we find the frequency dependence of the source fluxes to be if both Sv ∝ v^(2.6 (0.4)/-0.2)) experiments measure the same population of sources. Simultaneously fitting for the amplitude of the SZE power spectrum and a Poisson-distributed point source population, we place an upper limit on the matter fluctuation amplitude of σ(8) < 1.18 at 95% confidence.