paper

The Giant Metrewave Radio Telescope Cold-HI AT Survey

arXiv:2207.00031 · doi:10.3847/1538-4357/ac7d52

Abstract

We describe the design, data analysis, and basic results of the Giant Metrewave Radio Telescope Cold-HI AT (GMRT-CAT1) survey, a 510-hour upgraded GMRT HI 21 cm emission survey of galaxies at in the DEEP2 survey fields. The GMRT-CAT1 survey is aimed at characterising HI in galaxies during and just after the epoch of peak star-formation activity in the Universe, a key epoch in galaxy evolution. We obtained high-quality HI 21 cm spectra for 11,419 blue star-forming galaxies at , in seven pointings on the DEEP2 subfields. We detect the stacked HI 21 cm emission signal of the 11,419 star-forming galaxies, which have an average stellar mass of , at statistical significance, obtaining an average HI mass of . This is significantly higher than the average HI mass of in star-forming galaxies at with an identical stellar-mass distribution. We stack the rest-frame 1.4 GHz continuum emission of our 11,419 galaxies to infer an average star-formation rate (SFR) of . Combining our average HI mass and average SFR estimates yields an HI depletion timescale of Gyr, for star-forming galaxies at , times lower than that of local galaxies. We thus find that, although main-sequence galaxies at have a high HI mass, their short HI depletion timescale is likely to cause quenching of their star-formation activity in the absence of rapid gas accretion from the circumgalactic medium.

27 pages, 15 figures; The Astrophysical Journal, 937, 103; updated to match published version

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