Annual Report_Abridged - Second Version - FINAL

17 lines to characterize the properties of cold atomic andmolecular gas associatedwith AGN The MALS team led by Neeraj Gupta has released radio continuum images and a catalog of 495,325 radio sources detected over an area of 2289 deg2 from 391 telescope pointings at 1 - 1.4 GHz. “Majority of these radio sources are AGNs and many are detected for the first time, thanks to excellent capabilities of MeerKAT. These radio sources will subsequently be used as background targets to detect signatures of cold gas in and around galaxies, addressing the main theme of the survey.” – explains Partha Pratim Deka, currently a PhD student at IUCAA, Pune and the lead-author of the Astrophysical Journal article describing the data release. The MALS catalogs and images are publicly available at https://mals.iucaa.in. These may be Cold Molecules in HI 21-cm Absorbers across Redshifts0.1-4 Absorption lines at high redshift in front of quasars are rare in the mm domain. Only five associated and five intervening systems have been reported in the literature. These bring very useful information complementary to emission lines, for instance, to distinguish between inflows and outflows. They are also good candidates to study the variations of the fundamental constants. Neeraj Gupta and his collaborators report the search for molecules in emission and absorption in front of a sample of 30 targets, comprising 16 associated and 14 intervening HI 21-cm absorbers. The observations have been done w i t h t he I RAM- 30m t e l e s c op e , simultaneously at 3mm and 2mm, exploring CO ladder and HCO+ lines. Eight targets have been detected in emission, of which five are new. Their molecular gas masses range from 109 to 7 1011 Mo. We also report four new detections in absorption. Two of the associated CO absorption line detections at high redshift (z=1.211 and 1.275) resulted from the high spatial resolution follow-up with NOEMA. The disparity between the mm molecular and HI 21-cm absorption lines for these and another intervening systemdetected in HNC at z = 1.275, is attributable to radio and mm sight lines tracing different media. Comparing HI and H2 in the 14 known high redshift molecular absorbers, associated HI absorption lines are broad, with multiple components and the molecular absorption corresponds to the broader and weaker 21-cm absorption component. This indicates two distinct phases: one near galaxy used for a diverse range of scientific objectives by the astronomy community.