Beyond assembly bias: exploring secondary halo biases for cluster-size haloes

Journal Article · Fri Dec 01 00:00:00 EST 2017 · Monthly Notices of the Royal Astronomical Society

DOI:https://doi.org/10.1093/mnras/stx3111· OSTI ID:1423516

Mao, Yao-Yuan ^[1]; Zentner, Andrew R. ^[1]; Wechsler, Risa H. ^[2]

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1. Univ. of Pittsburgh, PA (United States). Pittsburgh Particle Physics, Astrophysics and Cosmology Center (PITT PACC), Dept. of Physics and Astronomy; Univ. of California, Santa Barbara, CA (United States). Kavli Inst. for Theoretical Physics
2. Univ. of California, Santa Barbara, CA (United States). Kavli Inst. for Theoretical Physics; Stanford Univ., CA (United States). Kavli Inst. for Particle Astrophysics and Cosmology and Dept. of Physics; SLAC National Accelerator Lab., Menlo Park, CA (United States)

Secondary halo bias, commonly known as ‘assembly bias’, is the dependence of halo clustering on a halo property other than mass. This prediction of the Λ Cold Dark Matter cosmology is essential to modelling the galaxy distribution to high precision and interpreting clustering measurements. As the name suggests, different manifestations of secondary halo bias have been thought to originate from halo assembly histories. We show conclusively that this is incorrect for cluster-size haloes. We present an up-to-date summary of secondary halo biases of high-mass haloes due to various halo properties including concentration, spin, several proxies of assembly history, and subhalo properties. While concentration, spin, and the abundance and radial distribution of subhaloes exhibit significant secondary biases, properties that directly quantify halo assembly history do not. In fact, the entire assembly histories of haloes in pairs are nearly identical to those of isolated haloes. In general, a global correlation between two halo properties does not predict whether or not these two properties exhibit similar secondary biases. For example, assembly history and concentration (or subhalo abundance) are correlated for both paired and isolated haloes, but follow slightly different conditional distributions in these two cases. Lastly, this results in a secondary halo bias due to concentration (or subhalo abundance), despite the lack of assembly bias in the strict sense for cluster-size haloes. Due to this complexity, caution must be exercised in using any one halo property as a proxy to study the secondary bias due to another property.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States). Oak Ridge Leadership Computing Facility (OLCF); SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC); National Science Foundation (NSF); National Aeronautics and Space Administration (NASA)
• Grant/Contract Number: AC02-76SF00515; 1516266; 1517563; PHY-1125915
• OSTI ID: 1423516
• Journal Information: Monthly Notices of the Royal Astronomical Society, Vol. 474, Issue 4; ISSN 0035-8711
• Publisher: Royal Astronomical Society
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
methods: numerical
galaxies: clusters: general
galaxies: formation
galaxies: haloes
dark matter
large-scale structure of Universe