Suzaku Observations of Metallicity Distribution in the Intracluster Medium of the NGC 5044 Group

Abstract

The metallicity distribution in the intracluster medium of the NGC 5044 group was studied up to 0.3 r180 using the XIS instrument aboard the Suzaku satellite. The abundances of O, Mg, Si, S, and Fe were measured with high accuracy. The region within a radius of 0.05 r180 from the center shows approximately solar abundances of Mg, Si, S, and Fe, while the O/Fe ratio is about 0.5-0.6 in solar units. In the outer region, the Fe abundance gradually drops to 0.3 solar. The radial abundance profiles of Mg, Si and S are similar to that of Fe, while that of O seems to be flatter. At r > 0.05 r 180, the mass density profile of O differs from that of Fe, showing a shoulder-like structure that traces the luminosity density profile of galaxies. The mass-to-light ratios for O and Fe in NGC 5044 are one of the largest among groups of galaxies, but they are still smaller than those in rich clusters. These abundance features probably reflect the metal enrichment history of this relaxed group hosting a giant elliptical galaxy in the center. © 2009. Astronomical Society of Japan.