Exploring the gaseous coronae of galaxies using absorption studies
Abstract
Galaxy formation models predict the existence of gaseous coronae in dark matter halos around galaxies, which coronae extend to large radii. For massive galaxies the shock-heated gas may emit in the X-ray regime. Due to its long cooling time, the dominant fraction of the large-scale gas remains quasi-static, and should be observable at the present epoch. However, the overall characteristics of these coronae are poorly understood. Although hot gaseous halos were explored around a handful of massive spiral galaxies, these observations explore the coronae only out to about 15% of the virial radius. Therefore, these individual observations shed light only on a few percent of the total gas mass in the corona, while most of the gas remains unexplored. A promising approach to probe the outer parts of the halos is to perform absorption studies. The strongest transitions from the hot gas are expected from the O VII, C V, and Ne IX ions. In this work we utilize Chandra LETG and XMM-Newton RGS observations along with the known redshift of foreground absorption line systems to carry out a systematic study of luminous background quasars. The goal of this study is to identify absorption lines that may originate from the gaseous coronae of foreground galaxies, which could play a key role in understanding the characteristics of the hot gaseous coronae.
- Publication:
-
AAS/High Energy Astrophysics Division #16
- Pub Date:
- August 2017
- Bibcode:
- 2017HEAD...1610717K