ROSAT Observations of Distant Clusters of Galaxies

Abstract

view Abstract Citations (18) References (51) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS ROSAT Observations of Distant Clusters of Galaxies Donahue, Megan ; Stocke, John T. Abstract We present the results of ROSAT Position Sensitive Proportional Counter and High Resolution Imager observations of two distant clusters of galaxies, MS 0735 + 74 and MS 0451-03, selected from the Einstein Extended Medium-Sensitivity Survey (EMSS). The cluster MS 0735+74 at z = 0.216 is a cooling flow candidate because the central brightest galaxy has extended Hα emission. We present optical spectra and a radio map for this cluster's brightest cluster galaxy. MS 0451-03, at a newly determined redshift of z = 0.55, is the most luminous cluster in the EMSS with Lχ(0.5 3.5 keV) = 2.0 × 1045 ergs s-1 h50-2. We derive significant limits on gas temperatures in these clusters and measure their core radii, "βimage" and mass cooling rates. We estimate gas masses and total gravitational masses for each cluster. We quantify structure by fitting isophotal ellipses and by decomposing the images with a wavelet analysis. The clusters are elliptical, but we measure no other significant substructure. In the cluster MS 0735+74 we compare the structure and flux from the central optical emission-line nebulosity to the cluster's X-ray and radio emission from the same region. We discuss the significance of the measured X-ray properties in the context of cluster evolution and cooling flows. Our results show that "cooling flows" can be identified by their extended Hα emission and that distant clusters probably do not have more intrinsic absorption than nearby clusters. We suggest that these distant clusters have X-ray morphologies similar to those of rich nearby clusters and that MS 0451-03, a luminous cluster at high redshift, may have somewhat lower Mgas/Mtotal ratios (≲17% at 1 h50-1 Mpc scales) than low-redshift clusters of comparable luminosity. Publication: The Astrophysical Journal Pub Date: August 1995 DOI: 10.1086/176079 Bibcode: 1995ApJ...449..554D Keywords: GALAXIES: COOLING FLOWS; GALAXIES: CLUSTERS: INDIVIDUAL ALPHANUMERIC: MS 0735+74; GALAXIES: CLUSTERS: INDIVIDUAL ALPHANUMERIC: MS 0415-3; X-RAYS: GALAXIES full text sources ADS | data products SIMBAD (6) NED (2) HEASARC (1)