| Title: |
Mapping HI 21-cm in the Klemola 31 group at z = 0.029: emission and absorption towards PKS2020-370 |
| Authors: |
Maina, E. K., Mohapatra, Abhisek, Jozsa, G. I. G., Gupta, N., Combes, F., Deka, P., Wagenveld, J. D., Srianand, R., Balashev, S. A., Chen, Hsiao-Wen, Krogager, J. -K., Momjian, E., Noterdaeme, P., Petitjean, P. |
| Publication Year: |
2022 |
| Collection: |
Astrophysics |
| Subject Terms: |
Astrophysics - Astrophysics of Galaxies |
| More Details: |
We present MeerKAT Absorption Line Survey (MALS) observations of the HI gas in the Klemola31 galaxy group ($z=0.029$), located along the line of sight to the radio-loud quasar PKS2020-370 ($z=1.048$). Four galaxies of the group are detected in HI emission, and HI absorption is also detected in front of PKS2020-370 in Klemola31A. The emission and absorption are somewhat compensating on the line of sight of the quasar, and the derived column density of the absorption appears under-estimated, with respect to the neighbouring emission. A symmetric tilted-ring model of Klemola31A, assuming the absorbing gas in regular rotation in the plane, yields a rather high spin temperature of 530K. An alternative interpretation is that the absorbing gas is extra-planar, which will also account for its non-circular motion. The NaI/CaII ratio also suggests that the absorbing gas is unrelated to cold HI disk. Two of the galaxies in the Klemola group are interacting with a small companion, and reveal typical tidal tails, and velocity perturbations. Only one of the galaxies, ESO400-13, reveals a strong HI deficiency, and a characteristic ram-pressure stripping, with a total asymmetry in the distribution of its gas. Since a small galaxy group as Klemola31 is not expected to host a dense intra-group gas, this galaxy must be crossing the group at a very high velocity, mostly in the sky plane.
Comment: 13 pages, 8 figures, 3 tables, accepted in MNRAS (minor corrections) |
| Document Type: |
Working Paper |
| DOI: |
10.1093/mnras/stac1752 |
| Access URL: |
http://arxiv.org/abs/2206.09940 |
| Accession Number: |
edsarx.2206.09940 |
| Database: |
arXiv |
