Detection of an H i Disk in Hydra A?
Abstract
We present new observations of the H I absorption system seen toward the core of the radio galaxy Hydra A, which is the central galaxy in a cooling flow cluster Abell 780. Our improved spatial (~2") and velocity (~1.4 km s^-1^) resolutions indicate that the absorption arises very close to the nucleus, probably in a gas disk located in the central regions of the galaxy. There is no indication that any of the absorption arises in the cooling flow. The H I absorption is seen only toward the core and is within ~100 km s^-1^ of the systemic velocity. The absorption covers a velocity range ~100 km s^-1^. It can be decomposed into six Gaussian components with widths ~10-20 km s^-1^ and optical depths ~0.1-0.5. No narrow line features (~1 km s^-1^) were detected in Hydra A to a 3 σ optical depth limit of 0.06.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- March 1995
- DOI:
- 10.1086/187801
- Bibcode:
- 1995ApJ...442L...1D
- Keywords:
-
- Absorption Spectra;
- Cooling Flows (Astrophysics);
- Disk Galaxies;
- H I Regions;
- Radio Galaxies;
- Galactic Clusters;
- Stellar Spectra;
- Velocity Distribution;
- Astronomy;
- RADIO LINES: GALAXIES;
- GALAXIES: COOLING FLOWS;
- GALAXIES: INDIVIDUAL NAME: HYDRA A