X‐Ray Properties of the Abell 644 Cluster of Galaxies

Franz Bauer, Craig L. Sarazin
2000 Astrophysical Journal  
We use new ASCA observations and archival ROSAT Position Sensitive Proportional Counter (PSPC) data to determine the X-ray spectral properties of the intracluster gas in Abell 644. From the overall spectrum, we determine the average gas temperature to be 8.64 (+0.67,-0.56) keV, and an abundance of 0.32 (+/-0.04) Z_. The global ASCA and ROSAT spectra imply a cooling rate of 214 (+100,-91) M_ yr^-1. The PSPC X-ray surface brightness profile and the ASCA data suggest a somewhat higher cooling
more » ... We determine the gravitational mass and gas mass as a function of radius. The total gravitating mass within 1.2 Mpc is 6.2×10^14 M_, of which 20 is in the form of hot gas. There is a region of elevated temperature 1.5-5 arcmin to the west of the cluster center. The south-southwest region of the cluster also shows excess emission in the ROSAT PSPC X-ray image, aligned with the major axis of the optical cD galaxy in the center of the cluster. We argue that the cluster is undergoing or has recently undergone a minor merger. The combination of a fairly strong cooling flow and evidence for a merger make this cluster an interesting case to test the disruption of cooling flow in mergers.
doi:10.1086/308354 fatcat:wtfdflktbvg4lpb3om7h6ugvyu