Cool Core Bias in Sunyaev-Zel’dovich Galaxy Cluster Surveys

Journal Article · Wed Mar 18 00:00:00 EDT 2015 · The Astrophysical Journal (Online)

DOI:https://doi.org/10.1088/0004-637X/802/1/34· OSTI ID:1226318

Lin, Henry W. ^[1]; McDonald, Michael ^[2]; Benson, Bradford ^[3]; Miller, Eric ^[2]

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1. Harvard Univ., Cambridge, MA (United States)
2. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Kavli Inst. of Astrophysics and Space Research
3. Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

Sunyaev-Zeldovich (SZ) surveys find massive clusters of galaxies by measuring the inverse Compton scattering of cosmic microwave background off of intra-cluster gas. The cluster selection function from such surveys is expected to be nearly independent of redshift and cluster astrophysics. In this work, we estimate the effect on the observed SZ signal of centrally-peaked gas density profiles (cool cores) and radio emission from the brightest cluster galaxy (BCG) by creating mock observations of a sample of clusters that span the observed range of classical cooling rates and radio luminosities. For each cluster, we make simulated SZ observations by the South Pole Telescope and characterize the cluster selection function, but note that our results are broadly applicable to other SZ surveys. We find that the inclusion of a cool core can cause a change in the measured SPT significance of a cluster between 0.01%–10% at z > 0.3, increasing with cuspiness of the cool core and angular size on the sky of the cluster (i.e., decreasing redshift, increasing mass). We provide quantitative estimates of the bias in the SZ signal as a function of a gas density cuspiness parameter, redshift, mass, and the 1.4 GHz radio luminosity of the central AGN. Based on this work, we estimate that, for the Phoenix cluster (one of the strongest cool cores known), the presence of a cool core is biasing the SZ significance high by ~6%. The ubiquity of radio galaxies at the centers of cool core clusters will offset the cool core bias to varying degrees

• Research Organization: Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
• Sponsoring Organization: USDOE Office of Science (SC), High Energy Physics (HEP)
• Grant/Contract Number: AC02-07CH11359
• OSTI ID: 1226318
• Report Number(s): FERMILAB-PUB-15-053-A; arXiv eprint number arXiv:1501.04650
• Journal Information: The Astrophysical Journal (Online), Vol. 802, Issue 1; ISSN 1538-4357
• Publisher: Institute of Physics (IOP)
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS