Name: Partha Pratim Deka
Affiliation: Inter-University Center for Astronomy and Astrophysics
Conference ID : ASI2022_213
Title : An unbiased view of cold atomic gas associated with radio loud AGNs up-to z~2 using MALS.
Authors : Partha Pratim Deka (IUCAA), 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 0200 mJy) selected through a SALT-NOT survey. The careful target selection and overlap with various multi-wavelength surveys such as WISE, DESI and GALEX will help in revealing the nature of AGN and its host galaxy. In this talk, I will present the MALS footprint based on the SALT-NOT survey and the sample of ~30,000 bright AGNs (>1 mJy) detected in ~400 pointings that are suitable for associated HI 21-cm absorption line search. We have used a subset of these for astrometric and flux scale characterization of MALS. I will summarize these technical results. Through the full sample, we expect ~500 associated HI absorption detections spanning the full column density range: N(HI) ~ 10^19 - 10^22 cm^-2, for a wide range of AGN luminosities (down-to ~10^21 W/Hz at 1.4 GHz), covering both FRI/II and high/low- excitation galaxies. The sample will thus allow detection of cold gas over a wide range of AGN evolutionary stages and types. Finally, I will present in detail the very first serendipitous detection of a new 21-cm associated absorber at z=1.354, where the complexity of the absorption profile reveals the interaction between the AGN and its surrounding cold gas.