Testing the Large-scale Environments of Cool-core and Non-cool-core Clusters with Clustering Bias

Journal
Date Issued
2017
Author(s)
Medezinski, Elinor
•
Battaglia, Nicholas
•
Coupon, Jean
•
Cen, Renyue
•
•
Strauss, Michael A.
•
Spergel, David N.
DOI
Abstract
There are well-observed differences between cool-core (CC) and non-cool-core (NCC) clusters, but the origin of this distinction is still largely unknown. Competing theories can be divided into internal (inside-out), in which internal physical processes transform or maintain the NCC phase, and external (outside-in), in which the cluster type is determined by its initial conditions, which in turn leads to different formation histories (I.e., assembly bias). We propose a new method that uses the relative assembly bias of CC to NCC clusters, as determined via the two-point cluster-galaxy cross-correlation function (CCF), to test whether formation history plays a role in determining their nature. We apply our method to 48 ACCEPT clusters, which have well resolved central entropies, and cross-correlate with the SDSS-III/BOSS LOWZ galaxy catalog. We find that the relative bias of NCC over CC clusters is b = 1.42 ± 0.35 (1.6σ different from unity). Our measurement is limited by the small number of clusters with core entropy information within the BOSS footprint, 14 CC and 34 NCC clusters. Future compilations of X-ray cluster samples, combined with deep all-sky redshift surveys, will be able to better constrain the relative assembly bias of CC and NCC clusters and determine the origin of the bimodality.
Volume
836
Issue
1
Start page
54
Uri
Url
Issn Identifier
0004-637X
Ads BibCode
2017ApJ...836...54M
Rights
open.access
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