题　  目：Explore the Origin of Galactic Coronae with a Chandra Survey of Nearby Highly-Inclined Disc Galaxies

报 告 人：李江涛 博士 (UMASS, CEA Saclay)

报告时间：4月18日周四上午9：30

报告地点：苏福特一楼会议室

报告摘要：There are two scenarios for the formation of corona around disc galaxies, either from accretion of the IGM or from galactic feedbacks. We analyze Chandra data of 53 nearby highly-inclined disc galaxies and study the correlation of their coronal properties with other galaxy properties. We further compare the results to those obtained for elliptical galaxies and from cosmological simulations. We find good correlations of the coronal luminosity LX with the SFR and the total SN energy input rate from core collapsed (CC) and Ia SNe. The X-ray radiation efficiency has a mean value of ~0.4% and correlates with the baryonic-to-stellar mass ratio MTF/M* and the CC SN rate surface density, reflecting the opposite effects of mass and feedback concentrations in regulating the coronal X-ray emission, and/or the importance of cool-hot gas interaction. Early-type non-starburst disc galaxies tend to be more Fe-rich, while starburst ones have similar Fe/O ratios of ~0.4solar. The combined LX-M* relation of observed and simulated galaxies show a similar shape as the stellar-mass-halo-mass-relation, i.e., with different slopes above and below a transition mass of M*~1e11 Msolar. Our results suggest that the coronae of our sample galaxies are consistent with SN feedback in origin, but it is still possible to detect accretion-induced coronae from more massive disc galaxies.

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　　　　　　　　　　　　　　　　　　　　　　　　　　 南京大学天文与空间科学学院