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The neutral hydrogen view of dwarf galaxies: the baryonic Tully-Fisher relation

PAA 102

Betsey Adams (Netherlands Institute for Radio Astronomy)

May 19 @ 3:30 PM - 4:30 PM

Dwarf galaxies are important testbeds for galaxy formation and cosmology. With their small sizes and low gravitational potential wells, they are extremely susceptible to feedback and disruption. Discrepancies between observations of dwarf galaxies and results from simulations have been used to test our cosmological model and as motivation to improve the resolution and feedback implementation of simulations. The current era of large, blind neutral hydrogen (HI) surveys hold a lot of promise for studies of dwarf galaxies. HI surveys preferentially select isolated, field galaxies, providing a strong complement to existing in-depth studies of dwarf galaxies near more massive galaxies. Practically, HI is observed as a spectral line, so it offers a measure of the internal kinematics of a source, critical for constraining the dark matter halo and connecting observations to simulations. One key example is the behavior of dwarf galaxies on the baryonic Tully-Fisher relation, which relates total baryonic mass to rotational velocity, and I will highlight how two different HI-selected dwarf galaxy populations from the ALFALFA HI survey can test our understanding of this fundamental relation. The Survey of HI in Extremely Low-mass Dwarfs (SHIELD) targets the 82 lowest HI-mass galaxies from ALFALFA and populates the low-mass end of the relation, where LCDM simulations predict the relation should change. HI-bearing ultra-diffuse galaxies, selected for their low (optical) surface brightness and extended (optical) sizes, are outliers of the relation, having low rotation velocities for their baryonic mass. I will also discuss the exciting future for HI studies of dwarf galaxies with recent and ongoing surveys such as the Apertif imaging surveys and the HI emission component of the MIGHTEE survey.

This talk will be in hybrid format. Please contact the department office for Zoom information.