Intrinsic scatter of caustic masses and hydrostatic bias: An observational study

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dc.contributor.authorAndreon, Stefano
dc.contributor.authorTrinchier, G.
dc.contributor.authorWang, Jingying
dc.date.accessioned2023-07-03T10:01:32Z
dc.date.available2023-07-03T10:01:32Z
dc.date.issued2017
dc.description.abstractAll estimates of cluster mass have some intrinsic scatter and perhaps some bias with true mass even in the absence of measurement errors for example caused by cluster triaxiality and large scale structure. Knowledge of the bias and scatter values is fundamental for both cluster cosmology and astrophysics. In this paper we show that the intrinsic scatter of a mass proxy can be constrained by measurements of the gas fraction because masses with higher values of intrinsic scatter with true mass produce more scattered gas fractions. Moreover, the relative bias of two mass estimates can be constrained by comparing the mean gas fraction at the same (nominal) cluster mass. Our observational study addresses the scatter between caustic (i.e., dynamically estimated) and true masses, and the relative bias of caustic and hydrostatic masses. For these purposes, we used the X-ray Unbiased Cluster Sample, a cluster sample selected independently from the intracluster medium content with reliable masses: 34 galaxy clusters in the nearby (0.050 < z < 0.135) Universe, mostly with 14 < log M500/M . 14.5, and with caustic masses. We found a 35% scatter between caustic and true masses. Furthermore, we found that the relative bias between caustic and hydrostatic masses is small, 0.06 ± 0.05 dex, improving upon past measurements. The small scatter found confirms our previous measurements of a highly variable amount of feedback from cluster to cluster, which is the cause of the observed large variety of core-excised X-ray luminosities and gas masses.en_US
dc.identifier.citationAndreon, S. et al. (2017). Intrinsic scatter of caustic masses and hydrostatic bias: An observational study. Astronomy & Astrophysics, A 606, A25. 10.1051/0004-6361/201730920en_US
dc.identifier.issn1432-0746
dc.identifier.uri10.1051/0004-6361/201730920
dc.identifier.urihttp://hdl.handle.net/10566/9180
dc.language.isoenen_US
dc.publisherEDP Sciencesen_US
dc.subjectAstronomyen_US
dc.subjectStatistics studiesen_US
dc.subjectGalaxies formationen_US
dc.subjectCosmologyen_US
dc.subjectPhysicsen_US
dc.titleIntrinsic scatter of caustic masses and hydrostatic bias: An observational studyen_US
dc.typeArticleen_US

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