The MeerKAT Absorption Line Survey (MALS) consists of 1655 hrs of MeerKAT time (anticipated raw data ~ 1.7 PB) to carry out the most sensitive search of HI and OH absorption lines at 0<z<2, the redshift range over which most of the cosmic evolution in the star formation rate density takes place. The MALS survey is described in Gupta et al. (2016). I am leading the H I emission project from MALS.
Publications
Mapping HI 21-cm in the Klemola 31 group at z = 0.029: emission and absorption towards PKS 2020-370
Maina, E. K.; Mohapatra, Abhisek; Józsa, 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.
We present MeerKAT Absorption Line Survey (MALS) observations of the HI gas in the Klemola 31 galaxy group (z = 0.029), located along the line of sight to the radio-loud quasar PKS 2020-370 (z = 1.048). Four galaxies of the group are detected in HI emission, and HI absorption is also detected in front of PKS 2020-370 in Klemola 31A. A symmetric tilted-ring model of Klemola 31A, assuming the absorbing gas in regular rotation in the plane, yields a rather high spin temperature of 530 K. An alternative interpretation is that the absorbing gas is extra-planar, which will also account for its non-circular motion. Only one of the galaxies, ESO 400-13, 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 Klemola 31 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.
