Temperature and Metallicity in the Intra-Cluster Medium of Abell 262 Observed with Suzaku

Abstract

We studied the temperature and abundance distributions of the intra-cluster medium (ICM) in the Abell 262 cluster of galaxies observed with Suzaku. Abell 262 is a bright, nearby poor cluster with an ICM temperature of ̃ 2 keV, thus providing useful information about the connection of ICM properties between groups and clusters of galaxies. With the XIS instrument, we directly measured not only the Si, S, and Fe lines, but also the O and Mg lines, and obtained those abundances to an outer region of ̃0.43 r180 for the first time. We found steep gradients for Mg, Si, S, and Fe abundances, while O showed an almost flat abundance distribution. The abundance ratios of α-elements to Fe were found to be similar to those of the other clusters and groups. We calculated the number ratio of type II to type la supernovae for the ICM enrichment to be 3.0 ± 0.6 within 0.1 r180; the value was consistent with those for other clusters and groups. We also calculated the metal mass-to-light ratios (MLRs) for Fe, O, and Mg with B-band and K-band luminosities of the member galaxies of Abell 262. The derived MLRs were comparable to those for other clusters with kT = 3-4 keV. © 2009. Astronomical Society of Japan.