The L_X-M relation of Clusters of Galaxies

Rykoff, E.S. ; Evrard, A.E. ; McKay, T.A. ; Becker, M.R. ; Johnston, D.E. ; Koester, B.P. ; Nord, B. ; Rozo, E. ; Sheldon, E.S. ; Stanek, R. ; Wechsler, R.H.

Stanford Linear Accelerator Center

关键词: Cosmology;    Galaxies;    Hydrostatics;    71 Classical And Quantum Mechanics, General Physics;    Astrophysics,Astro;   

DOI  :  10.2172/928354
RP-ID  :  SLAC-PUB-13238
RP-ID  :  AC02-76SF00515
RP-ID  :  928354

美国|英语

来源: UNT Digital Library

【 摘 要 】

We present a new measurement of the scaling relation between X-ray luminosity and total mass for 17,000 galaxy clusters in the maxBCG cluster sample. Stacking sub-samples within fixed ranges of optical richness, N200, we measure the mean 0.1-2.4 keV X-ray luminosity, , from the ROSAT All-Sky Survey. The mean mass, , is measured from weak gravitational lensing of SDSS background galaxies (Johnston et al. 2007). For 9 {le} N{sub 200} < 200, the data are well fit by a power-law, /10{sup 42} h{sup -2} ergs{sup -1} = (12.6{sub -1.3}{sup +1.4}(stat) {+-} 1.6 (sys)) (/10{sup 14} h{sup -1} M{sub {circle_dot}}){sup 1.65{+-}0.13}. The slope agrees to within 10% with previous estimates based on X-ray selected catalogs, implying that the covariance in L{sub X} and N{sub 200} at fixed halo mass is not large. The luminosity intercept is 30%, or 2{sigma}, lower than determined from the X-ray flux-limited sample of Reiprich & Boehringer (2002), assuming hydrostatic equilibrium. This slight difference could arise from a combination of Malmquist bias and/or systematic error in hydrostatic mass estimates, both of which are expected. The intercept agrees with that derived by Stanek et al. (2006) using a model for the statistical correspondence between clusters and halos in a WMAP3 cosmology with power spectrum normalization {sigma}{sub 8} = 0.85. Similar exercises applied to future data sets will allow constraints on the covariance among optical and hot gas properties of clusters at fixed mass.