Cosmological Clusters:
Chandra and Sunyaev-Zel'dovich Estimates of the Baryon
Fraction in a Luminous X-ray Cluster at z=0.5
Megan Donahue(STScI, 3700 San Martin Drive, Baltimore, MD, 21218, donahue@stsci.edu, 410-338-4701), Jessica Gaskin, Marshall Joy, Sandeep Patel (MSFC), John P. Hughes (Rutgers), John T. Stocke (Univ. of Colorado)
[Contributed talk, 15min.]
Abstract
I will briefly review the improved EMSS high redshift temperature function based on new Chandra cluster temperatures, and its impact on cluster cosmological parameters.
I will describe our Chandra observations of the cluster MS0451-0321,
which, at z=0.5, is the most luminous cluster in the EMSS.
We determine the cluster gas density distribution, gas mass fraction,
and preliminary constraints on the universal baryon mass fraction,
,
from a
maximum likelihood joint fit to the interferometric Sunyaev-Zel'dovich
imaging data and Chandra X-ray observations.
The spatial resolution of Chandra allows us to explore
the variations in the hot gas density distribution from a standard 2-D
elliptical data profile, as well as deviations from isothermality in
the
gas temperature. By doing a joint fit we are able to limit
the amount of clumping allowed in the gas; our X-ray imaging analysis
also places estimates on the level of substructure in the gas
distribution.
We also discuss the X-ray point source in the field coincident with a SCUBA/submm source and a cluster radio source.
CATEGORY: CLUSTERS OF GALAXIES