Medezinski, ElinorElinorMedezinskiBattaglia, NicholasNicholasBattagliaCoupon, JeanJeanCouponCen, RenyueRenyueCenGASPARI, MASSIMOMASSIMOGASPARIStrauss, Michael A.Michael A.StraussSpergel, David N.David N.Spergel2020-12-292020-12-2920170004-637Xhttp://hdl.handle.net/20.500.12386/29285There 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.STAMPAenArticle10.3847/1538-4357/836/1/542-s2.0-85014393739000397304500006https://iopscience.iop.org/article/10.3847/1538-4357/836/1/542017ApJ...836...54MFIS/05 - ASTRONOMIA E ASTROFISICA