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Title: Impact of point source clustering on cosmological parameters with CMB anisotropies

Abstract

The faint radio point sources that are unresolved in cosmic microwave background (CMB) anisotropy maps are likely to be a biased tracer of the large-scale structure dark matter distribution. While the shot-noise contribution to the angular power spectrum of unresolved radio point sources is included either when optimally constructing the CMB angular power spectrum, as with WMAP data, or when extracting cosmological parameters, we suggest that clustering part of the point source power spectrum should also be included. This is especially necessary at high frequencies above 150 GHz, where the clustering of far-IR sources is expected to dominate the shot-noise level of the angular power spectrum at tens of arcminute angular scales of both radio and sub-mm sources. We make an estimate of source clustering of unresolved radio sources in both WMAP and ACBAR, and marginalize over the amplitude of source clustering in each CMB data set when model fitting for cosmological parameters. For the combination of WMAP 5-year data and ACBAR, we find that the spectral index changes from the value of 0.963{+-}0.014 to 0.959{+-}0.014 (at 68% C.L.) when the clustering power spectrum of point sources is included in model fits. While we find that the differences are marginalmore » with and without source clustering in current data, it may be necessary to account for source clustering with future data sets such as Planck, especially to properly model fit anisotropies at arcminute angular scales. If clustering is not accounted and point sources are modeled with a shot noise only out to l{approx}2000, the spectral index will be biased by about 1.5{sigma}.« less

Authors:
; ;  [1]; ;  [2]
  1. Center for Cosmology, Department of Physics and Astronomy, University of California, Irvine, California 92697 (United States)
  2. Dipartimento di Fisica 'G. Marconi' and INFN, sezione di Roma, Universita di Roma 'La Sapienza', Ple Aldo Moro 5, 00185, Roma (Italy)
Publication Date:
OSTI Identifier:
21250447
Resource Type:
Journal Article
Journal Name:
Physical Review. D, Particles Fields
Additional Journal Information:
Journal Volume: 78; Journal Issue: 4; Other Information: DOI: 10.1103/PhysRevD.78.043004; (c) 2008 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0556-2821
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; 99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE; AMPLITUDES; ANISOTROPY; COSMOLOGICAL CONSTANT; DISTRIBUTION; GHZ RANGE; NOISE; NONLUMINOUS MATTER; POINT SOURCES; RELICT RADIATION; SPECTRA

Citation Formats

Serra, Paolo, Cooray, Asantha, Amblard, Alexandre, Pagano, Luca, and Melchiorri, Alessandro. Impact of point source clustering on cosmological parameters with CMB anisotropies. United States: N. p., 2008. Web. doi:10.1103/PHYSREVD.78.043004.
Serra, Paolo, Cooray, Asantha, Amblard, Alexandre, Pagano, Luca, & Melchiorri, Alessandro. Impact of point source clustering on cosmological parameters with CMB anisotropies. United States. doi:10.1103/PHYSREVD.78.043004.
Serra, Paolo, Cooray, Asantha, Amblard, Alexandre, Pagano, Luca, and Melchiorri, Alessandro. Fri . "Impact of point source clustering on cosmological parameters with CMB anisotropies". United States. doi:10.1103/PHYSREVD.78.043004.
@article{osti_21250447,
title = {Impact of point source clustering on cosmological parameters with CMB anisotropies},
author = {Serra, Paolo and Cooray, Asantha and Amblard, Alexandre and Pagano, Luca and Melchiorri, Alessandro},
abstractNote = {The faint radio point sources that are unresolved in cosmic microwave background (CMB) anisotropy maps are likely to be a biased tracer of the large-scale structure dark matter distribution. While the shot-noise contribution to the angular power spectrum of unresolved radio point sources is included either when optimally constructing the CMB angular power spectrum, as with WMAP data, or when extracting cosmological parameters, we suggest that clustering part of the point source power spectrum should also be included. This is especially necessary at high frequencies above 150 GHz, where the clustering of far-IR sources is expected to dominate the shot-noise level of the angular power spectrum at tens of arcminute angular scales of both radio and sub-mm sources. We make an estimate of source clustering of unresolved radio sources in both WMAP and ACBAR, and marginalize over the amplitude of source clustering in each CMB data set when model fitting for cosmological parameters. For the combination of WMAP 5-year data and ACBAR, we find that the spectral index changes from the value of 0.963{+-}0.014 to 0.959{+-}0.014 (at 68% C.L.) when the clustering power spectrum of point sources is included in model fits. While we find that the differences are marginal with and without source clustering in current data, it may be necessary to account for source clustering with future data sets such as Planck, especially to properly model fit anisotropies at arcminute angular scales. If clustering is not accounted and point sources are modeled with a shot noise only out to l{approx}2000, the spectral index will be biased by about 1.5{sigma}.},
doi = {10.1103/PHYSREVD.78.043004},
journal = {Physical Review. D, Particles Fields},
issn = {0556-2821},
number = 4,
volume = 78,
place = {United States},
year = {2008},
month = {8}
}