Speaker
Description
HI studies have been longly limited to z<0.4 due to limited sensitivity of interferometric facilities, not deep enough to compensate for the intrinsic faintness of the 21-cm line. A computationally cost-effective alternative is stacking, which allows us to determine average HI properties of samples of galaxies beyond the detection limit. Pioneering works with MeerKAT, ASKAP, jVLA, and uGMRT have paved the way by tracking down HI properties for samples of star-forming galaxies, lying on the so-called Main Sequence, beyond the Local Universe. While Main Sequence galaxies have been a target for HI studies for several years already, quiescent galaxies have been largely neglected at z>0. Traditionally considered to contain little to no gas, HI content in quenched galaxies is a debated topic, with inhomogeneous and contradictory results across literature.
We propose a spectral stalking analysis of two separate, diverse samples of galaxies below the Main Sequence, selected with different criteria. We find evidence for a connection between HI and dust content, linking up with existing scenarios for gas rejuvenation. Moreover, we also find modest dependence of HI content on morphology and environment, building up on older results with diverse interpretations. Larger surveys with wider sky coverage may provide more statistically-robust samples, most suited to enhance our understanding of which parameters best drive HI content in quiescent galaxies. SKA-level sensitivities will put our view on HI properties forward in redshift.
| Topics | Galaxy Evolution & AGN |
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