Chandra Observations of the Massive Cluster MS2137.3-2353

M. W. Wise(MIT), B. R. McNamara (Ohio Univ.), J. C. Houck (MIT), A. K. Hicks (MIT),
D. S. Davis (MIT), and C. L. Sarazin (UVa)

Abstract

We report on a Chandra observation of the massive, medium redshift (z=0.313) cooling flow cluster MS2137.3-2353. MS2137.3-2353 was observed by Chandra using the ACIS-S for 43.6 ksec in order to search for evidence of accumulated cooled material from the purportedly large ( $\dot{M} _X \sim 1400 \ifmmode{\ifmmode{\ {\rm M}_\odot}\else{$\space {\rm M}_\... ...\ifmmode{\ {\rm M}_\odot}\else{$\space {\rm M}_\odot$ }\fi\ {\rm yr}^{-1}$ }\fi$) cooling flow. We confirm the presence of a steep temperature gradient in the central 240 kpc of the cluster. The temperature drops from an ambient value of $\sim 7.0$ keV at the cooling radius to a central value of $\sim 3.5$ keV. The ACIS spectra are best fit by a cooling flow model only in the cluster core with a total mass accretion rate of $\dot{M} _X \sim 300 \ifmmode{\ifmmode{\ {\rm M}_\odot}\else{$\space {\rm M}_\o... ...\ifmmode{\ {\rm M}_\odot}\else{$\space {\rm M}_\odot$ }\fi\ {\rm yr}^{-1}$ }\fi$. This value is a factor of $\sim 7$below the value of $1400 \ifmmode{\ifmmode{\ {\rm M}_\odot}\else{$\space {\rm M}_\odot$ }\fi\ {\rm ... ...\ifmmode{\ {\rm M}_\odot}\else{$\space {\rm M}_\odot$ }\fi\ {\rm yr}^{-1}$ }\fi$ reported by previous ASCA and ROSAT analyses. At larger radii, a single temperature thermal model provides an excellent fit. The spatially resolved spectra show some evidence for increased absorption relative to the Galactic value as a function of decreasing projected radius in the cluster. The measured level of $\Delta N_{\rm H}(r)$ is, however, less than implied by the measured $\dot{M} _X (r)$. We find no reliable evidence for an absorption edge in the ACIS PHA spectrum consistent with redshifted O K associated with accumulated cooled material. 2-D maps of the temperature, abundance, and absorbing columns are presented. In addition, MS2137.3-2353 has been studied extensively with HST due to the presence of strong radial arcs presumably produced by gravitational lensing. Such radial arcs are consistent with very small core radii ( $r_c \lesssim 50 ~h^{-1}_{50}$ kpc) in the underlying dark matter distribution and suggest that MS2137.3-2353 is likely a relaxed cluster. Comparisons between the X-ray derived mass from Chandra and previous estimates based on gravitational lensing show good agreement.

CATEGORY: CLUSTERS OF GALAXIES