AChandraStudy of the Effects of a Major Merger on the Structure of A2319

We present an analysis of a Chandra observation of the massive, nearby galaxycluster Abell 2319. A sharp surface brightness discontinuity--suggested byprevious, lower angular resolution X-ray imaging--is clearly visible in theACIS image. This roughly 300kpc feature suggests that a major merger is takingplace with a significant velocity component perpendicular to the line of sight.The cluster emission-weighted mean temperature is 11.8+/-0.6kev, somewhathigher than previous temperature measurements. The Chandra temperature map ofA2319 reveals substructure resembling that anticipated based on hydrodynamicsimulations of cluster mergers. The merger feature shows a pressure changeacross the surface brightness discontinuity by a factor of <=2.5. The higherdensity side of the front has a lower temperature, suggesting the presence of acold front similar to those in many other merging clusters. The velocity of thefront is roughly sonic. We compare bulk properties of the ICM and galaxies in A2319 to the sameproperties in a large sample of clusters as a way of gauging the effects of themajor merger. Interestingly, by comparing A2319 to a sample of 44 clustersstudied with the ROSAT PSPC we find that the X-ray luminosity, isophotal size,and ICM mass are consistent with the expected values for a cluster of itstemperature; in addition, the K-band galaxy light is consistent with thelight--temperature scaling relation derived from a sample of about 100 clustersstudied with 2MASS. Together, these results indicate either that the merger inA2319 has not been effective at altering the bulk properties of the cluster, orthat there are large but correlated displacements in these quantities.Comment: 11 pages, 8 figures, ApJ Submitte