Discovery of an Outstanding Disk in the cD Galaxy of the Hydra A Cluster
Abstract
The central cD galaxy of the Hydra A cluster has one of the most powerful active galactic nuclei (AGNs) in the nearby Universe (z lesssim; 0.2). We report on the discovery of a dust lane in the cD galaxy using Subaru telescope. The iʹ-band image shows the existence of a dark band of the size of 3.ʺ6 × 0.ʺ7 (4 kpc × 0.8 kpc), which appears to be quite similar to the dust lane observed in Centaurus A. The morphology indicates that the cold disk that seen as the dust lane is almost edge-on and rotates around the AGN. Since the minor axis of the dust lane is nearly parallel to the radio jets emerging from the AGN, the disk is probably feeding its gas into the central black hole. From the absorption, we estimate the hydrogen column density of the lane is NH = 2.0 × 1021 cm-2 , and the mass of the disk is ∼8 × 107 M⊙. The column density is consistent with constraints obtained from Chandra X-ray observations. The age of the disk is gtrsim; 4 × 107 yr. The position angle of the disk and the galaxy's photometric axis are misaligned, which may imply that the cold gas in the disk is brought via galaxy mergers. Our observations may indicate that the supply of cold gas by galaxy mergers is required for the most intensive feedback from AGNs.
- Publication:
-
Publications of the Astronomical Society of Japan
- Pub Date:
- December 2013
- DOI:
- 10.1093/pasj/65.6.L15
- arXiv:
- arXiv:1310.3349
- Bibcode:
- 2013PASJ...65L..15F
- Keywords:
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- galaxies: clusters: individual: Hydra A;
- galaxies: elliptical and lenticular;
- cD;
- galaxies: active;
- galaxies: ISM;
- X-rays: galaxies: clusters;
- Astrophysics - Astrophysics of Galaxies;
- Astrophysics - Cosmology and Nongalactic Astrophysics
- E-Print:
- Minor changes to match published version. Free access at http://pasj.oxfordjournals.org/ by March 3