EAS Publications Series
Volume 56, 2012The Role of the Disk-Halo Interaction in Galaxy Evolution: Outflow vs. Infall?
|Page(s)||309 - 312|
|Section||The Active Disk-Halo Connection: Infall vs. Outflows|
|Published online||17 September 2012|
Miguel A. de Avillez (ed)
EAS Publications Series, 56 (2012) 309–312
Are strong MgII Absorbers Signatures of Outflows?
1 Max-Planck-Institut für extraterrestrische Physik, Giessenbachstrasse, Garching 85748, Germany ;
2 Swinburne University of Technology, Hawthorn, Victoria 3122, Australia
3 Observatoire Astronomique de Marseille-Provence, 13388 Marseille Cedex 13, France
Low-ionization transitions such as the Mg iiλ2796/2803 doublet trace cold gas in the vicinity of galaxies. The exact physical origin of this cold gas traced by QSO absorption lines is debated. Does it trace gas in disks, halos, merger tails, and even in outflows? Recent studies of strong starbursts and post-starbursts at intermediate redshifts have shown that Mg ii are seen in outflows, with blue-shifted velocities ∼500 − 1500km s−1. Strong intervening Mg ii absorbers (with equivalent width Wrλ2796 > 1Å) may be tracing the denser and colder gas of starburst-driven outflows. Indeed, based on Mg ii statistics, our clustering analysis has shown that the host-galaxy mass is anti-correlated with the line-of-sight velocity Δv (as measured from Wrλ2796). If Mg ii absorbers were virialized in galaxy halos, a positive Mh–Wr correlation would have been observed. Our result thus shows that the Mg ii clouds are not virialized in the gaseous halos of the host-galaxies.
© EAS, EDP Sciences, 2012