Extragalactic source contributions to arcminute-scale Cosmic Microwave Background anisotropies

Abstract

Abstract. The possible contributions of the various classes of extragalactic sources (including, in addition to the canonical radio sources, GHz Peaked Spectrum sources, advection-dominated sources, starburst galaxies, high-redshift proto-spheroidal galaxies) to the arcminute scale fluctuations measured by the CBI, BIMA, and ACBAR experiments are discussed. At 30 GHz, fluctuations due to radio sources undetected by ancillary low-frequency surveys may be higher than estimated by the CBI and BIMA groups. High-redshift dusty galaxies, whose fluctuations may be strongly enhanced by the effect of clustering, could contribute to the BIMA excess signal, and dominate at 150 GHz (the ACBAR frequency). Moreover, in the present data situation, the dust emission of these high-redshift sources set an unavoidable limit to the detection of primordial CMB anisotropies at high multipoles, even at frequencies as low as 30 GHz. It is concluded that the possibility that the excess power at high multipoles is dominated by unsubtracted extragalactic sources cannot be ruled out. On the other hand, there is room for a contribution from the Sunyaev-Zeldovich effect within clusters of galaxies, with a density fluctuation amplitude parameter σ 8 consistent with the values preferred by current data.

Planckearly results. XIII. Statistical properties of extragalactic radio sources in thePlanckEarly Release Compact Source Catalogue

“…Assuming a Poisson distribution (clustering effects are reduced to negligible values by the very broad luminosity function of radio sources, e.g., Toffolatti et al 2005;de Zotti et al 2010) and simply scaling As it is apparent, the two values are very close to each other, within the 1σ level calculated for the overall population in the two sky areas considered here, and well inside the 1σ normalized Poisson error bars. We also checked that at flux densities below about 0.9-1.0 Jy statistically more relevant deviations from a uniform distribution begin to appear.…”

Secondary anisotropies of the CMB

“…Note, however, that the excess σ 8 only appears if we believe that the resulting excess CMB fluctuations at the CBI scales is due to SZ effect from galaxy clusters. It has indeed been pointed out (Toffolatti et al 2005, Douspis, Aghanim & Langer 2006 that SZ from clusters are only mildly needed if there are unremoved point sources below the detection limit. On a a more speculative note, non-Gaussianity in the primordial power spectrum can boost the SZ power spectrum at cluster scales up to CBI excess (Mathis, Diego & Silk 2004, Sadeh, Rephaeli & Silk 2006).…”

Cosmic Microwave Background Anisotropies: The Power Spectrum and Beyond

“…For higher multipoles only ACBAR and CBI experiments have enough resolution and the data seem to indicate an excess of power as compared to the model prediction. This excess can be interpreted as a contribution from secondary anisotropies coming from the SZ effect [28] or/and the emission of radio sources [231]. However, new multifrequency data at arcminutes resolution are necessary to confirm the excess and discriminate among possible causes.…”