Testing global ISM models: A detailed comparison of O VI column densities with fuse and copernicus data
- Author(s)
- Miguel A. de Avillez, Dieter Breitschwerdt
- Abstract
We study the O VI distribution in space and time in a representative section of the Galactic disk using three-dimensional adaptive mesh refinement hydrodynamic and magnetohydrodynamic simulations of the interstellar medium (ISM), including the disk-halo-disk circulation. The simulations describe a supernova-driven ISM on large (~ 10 kpc) and small (~ 1.25 pc) scales over a sufficiently large timescale (~400 Myr) in order to establish a global dynamical equilibrium. The O VI column density, N(O VI), is monitored through line-of-sight measurements at different locations in the simulated disk. One has been deliberately chosen to be inside of a hot bubble, like our own Local Bubble, while the other locations are random. We obtain a correlation between N(O VI) and distance, which is independent of the observer's vantage point in the disk. In particular, the location of the observer inside a hot bubble does not have any influence on the correlation, because the contribution of an individual bubble (with a typical extension of 100 pc) is negligibly small. We find a remarkable agreement between the O VI column densities (as a function of distance) and the averaged O VI density (~1.8 × 10 -8 cm-3) in the disk from our simulations and from the values observed with Copernicus and FUSE. Our results strongly support the important role of turbulent mixing in the distribution of O VI clumps in the ISM. Supernova-induced turbulence is quite strong and unavoidable due to shearing motions in the ISM, and it operates on a large range of scales. Œ 2005. The American Astronomical Society. All rights reserved.
- Organisation(s)
- Department of Astrophysics
- External organisation(s)
- Universidade de Évora
- Journal
- The Astrophysical Journal: an international review of astronomy and astronomical physics
- Volume
- 634
- ISSN
- 0004-637X
- Publication date
- 2005
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 103003 Astronomy
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/44ccb079-c85c-4731-8a79-a54e54212d32