Name: Abhisek Mohapatra
Affiliation: IUCAA, Pune
Conference ID : ASI2022_483
Title : An unbiased view of nearby galaxies in HI 21-cm emission through MALS
Authors : Abhisek Mohapatra and MALS collaboration.
Abstract Type: Poster
Abstract Category : Extragalactic Astronomy
Abstract : 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. Due to the wide field of view and excellent low surface brightness sensitivity of MeerKAT, MALS is expected to detect ~10000-15000 galaxies (z < 0.2) in HI emission. In this talk, I will describe the overarching science goals of the blind HI emission line component of MALS. I will present early science results based on ~8000 galaxies (z = 0.01 - 0.05) detected from the 370 pointings observed so far. Many of these galaxies have no optical photometric or spectroscopic redshifts. The faintest detection, as expected based on the MALS sensitivity, corresponds to log M (HI)~8 M⊙. I will present the distributions of HI flux, HI mass, and width of the HI emission line of the identified galaxies, and compare these with overlapping single-dish surveys like ALFALFA. The spatially resolved morphological and kinematics from MALS is enabling detailed investigations of various HI scaling relations and the underlying statistical properties, which will eventually serve as a test-bed for galaxy formation and evolution models. Additionally, we also have serendipitous detections of many interesting isolated galaxies/galaxy groups in both HI absorptions and emissions. I will discuss in detail one such example of the well-known quasar-galaxy pair PKS2020-370/Klemola31A. The foreground galaxy, Klemola31A, in this case is part of a seven-member galaxy group. In another case, through joint investigation involving multi-band observations such as HST, MUSE, and MeerKAT datasets we are able to characterize the spatially resolved, multi-phase gas properties of the ISM of a host dwarf galaxy associated with a low-z DLA.