The multi-phase gaseous halos of star forming late-type galaxies I. XMM-Newton observations of the hot ionized medium
- Author(s)
- Ralph Tüllmann, Wolfgang Pietsch, Jörn Rossa, Dieter Breitschwerdt, Ralf Juergen Dettmar
- Abstract
This study presents first results from an X-ray mini-survey carried out with XMM-Newton to investigate the diffuse Hot Ionized Medium in the halos of nine nearby star-forming edge-on spiral galaxies. Diffuse gaseous X-ray halos are detected in eight of our targets, covering a wide range of star formation rates from quiescent to starburst cases. For four edge-on spiral galaxies, namely NGC 3044, NGC 3221, NGC 4634, and NGC 5775, we present the first published high resolution/sensitivity detections of extended soft X-ray halos. EPIC X-ray contour maps overlaid onto Ha imaging data reveals that in all cases the presence of X-ray halos is correlated with extraplanar Diffuse Ionized Gas. Moreover, these halos are also associated with non-thermal cosmic ray halos, as evidenced by radio continuum observations. Supplemental UV-data obtained with the OM-telescope at 210 nm show Diffuse Ionized Gas to be well associated with UV emission originating in the underlying disk. Beside NGC 891, NGC 4634 is the second non-starburst galaxy with a diffuse soft X-ray halo (|z| = 4 kpc). In case of NGC 3877, for which we also present the first high resolution X-ray imaging data, no halo emission is detectable. EPIC pn spectra (0.3-12 keV) of the diffuse X-ray emission are extracted at different offset positions from the disk, giving evidence to a significant decrease of gas temperatures, electron densities, and gas masses with increasing distance to the plane. A comparison between dynamical and radiative cooling time scales implies that the outflow in all targets is likely to be sustained. We find very strong indications that spatially correlated multi-phase gaseous halos are created by star forming activity in the disk plane. In a forthcoming paper, we will present multi-frequency luminosity relations and evaluate key parameters which might trigger the formation of multi-phase galaxy halos. ΠESO 2006.
- Organisation(s)
- Department of Astrophysics
- External organisation(s)
- Max-Planck-Institut für extraterrestrische Physik, Space Telescope Science Institute, Ruhr-Universität Bochum (RUB)
- Journal
- Astronomy & Astrophysics
- Volume
- 448
- Pages
- 43-75
- No. of pages
- 33
- ISSN
- 0004-6361
- DOI
- https://doi.org/10.1051/0004-6361:20052936
- Publication date
- 2006
- Peer reviewed
- Yes
- Austrian Fields of Science 2012
- 103003 Astronomy
- Portal url
- https://ucrisportal.univie.ac.at/en/publications/ae71f386-435a-4109-bd02-edb5cb68bd3f