A New Cluster of Galaxies towards the Galactic Bulge, Suzaku J1759-3450

TL;DR

This paper reports the discovery and analysis of a new galaxy cluster, Suzaku J1759-3450, identified through X-ray observations and characterized by its thermal plasma properties and spatial extent.

Contribution

The study presents the identification of a new galaxy cluster using Suzaku and Chandra X-ray data, including spectral analysis and modeling of its spatial profile.

Findings

Detected a 6 keV emission line indicating a galaxy cluster at z=0.13.

Measured the cluster's temperature as 5.3 keV and luminosity as 4.3 x 10^44 erg/s.

Confirmed the source as a galaxy cluster based on spectral and spatial analysis.

Abstract

We observed an extended X-ray source designated as Suzaku J1759-3450 with the Suzaku and Chandra observations towards 1RXS J175911.0-344921, which is an unidentified X-ray source listed in the ROSAT Bright Source Catalogue. A conspicuous emission line at 6 keV was also found in the Suzaku J1759-3450 spectrum. Assuming the emission line to be K emission from He-like Fe ions, we inferred Suzaku J1759-3450 to be an extragalactic object located at z = 0.13. The radial profile of the surface brightness in the 0.5-10 keV band was explained well with an isothermal beta-model of r_c = 1.61' and beta = 0.78. The X-ray spectrum was well reproduced by an optically-thin thermal plasma with the electron temperature of kT_e = 5.3 keV attenuated by the photoelectric absorption of N_H = 2.3 x 10^21 cm^-2. The bolometric X-ray luminosity of L_X (r < r_500) = 4.3 x 10^44 erg s^-1 is consistent with that expected from the L_X-T relation of clusters of galaxies. In terms of the spatial extent, the X-ray spectrum, and the bolometric luminosity of the X-ray emitting gas, we concluded that Suzaku J1759-3450 is a new cluster of galaxies.