Simulating the Local Interstellar Medium

[摘要] The Local Interstellar Medium (LISM) in many ways exemplifies the diffuse ISM of the Galaxy and star forming galaxies in general. Though devoid of molecular gas, it includes warm gas, hot, supernova-heated gas and even cold neutral gas clouds. The complex of local interstellar clouds (CLIC), which includes the cloud that directly surrounds the heliosphere, is made up of warm, low density, partially ionized gas. These clouds have somehow come to be embedded within the hot Local Bubble, apparently having survived the passage of the shock that heated the gas. We describe our attempts to understand this surprising situation and to explain the thermal and ionization state of the CLIC as well as the state of the Local Bubble via hydrodynamical and photoionization modeling. We also discuss the broader implications of our results for the interaction of the different temperature-density phases in the diffuse ISM of galaxies.

[发布机构] Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge; MA; 02138, United States^1

[关键词] Density phasis;Ionization state;Local interstellar clouds;Local interstellar medium;Molecular gas;Partially-ionized gas;Photoionization models;Star forming galaxy