11月16日 CHANDRA SURVEY OF GALACTIC CORONAE AROUND NEARBY EDGE-ON DISK GALAXIES
题 目：CHANDRA SURVEY OF GALACTIC CORONAE AROUND NEARBY EDGE-ON DISK GALAXIES
报告人：李江涛 (Postdoc at UMASS, Amherst, USA)
摘 要：The X-ray emitting coronae in nearby galaxies are expected to be produced either by accretion from the IGM or by various galactic feedbacks. It is known that the total hot gas luminosity of these galaxies is correlated with the stellar mass for early-type galaxies and with SFR for active star forming galaxies. However, such relations always have large scatter, indicating various other processes must be involved in regulating the coronal properties. In this work, we conduct a systematical analysis of the Chandra data of 53 nearby edge-on disk galaxies. The data are reduced in a uniform manner. Various coronal properties, such as the luminosity, temperature, emission measure, vertical and horizontal extension, and other derived parameters, are characterized for most of the sample galaxies. For some galaxies with high enough counting statistics, we also study the thermal and chemical states of the coronal gas. We then compare these hot gas properties to other galactic properties to further study the role of different processes in producing and/or maintaining the coronae. The soft X-ray luminosity of the coronae generally correlates well with the SFR over more than 3 orders of magnitude in SFR or Lx. In addition, the inclusion of other galactic properties could significantly improve the correlation of the SFR-Lx elation. The SN feedback efficiency is at most 10% for all the sample galaxies. We also find evidence for the effects of old stellar feedback, gravitation, environment, and cold-hot gas nteraction in regulating the coronal properties.