Speaker: Jingyao Zhu (Columbia)
The HI content and ram pressure stripping in dwarf satellite galaxies
Dwarf galaxies are excellent probes for astrophysics as they are abundant in number and sensitive to environments. Dwarf galaxies as satellites around extragalactic spirals have been extensively surveyed in recent years, which show a surprisingly large diversity in their quenched fractions. We present a new sample of gas-containing dwarf satellites with deep 21-cm HI data from two SKA-precursor surveys, MHONGOOSE and WALLABY. Combined with a previous ALFALFA sample, this sample contains over 100 gaseous dwarf satellites around 48 nearby spiral or Magellanic-like hosts. 90% of the hosts contain only a few (0–4) gas-containing satellites, indicating efficient gas loss/quenching.
To investigate the gas loss process, we conducted hydrodynamical “wind tunnel” simulations of dwarf satellites with multiphase gas undergoing ram pressure stripping (RPS) in Milky Way-like halos. We compare gas loss via external (RPS) and internal (star formation feedback) mechanisms. We constrain the complete gas stripping/quenching conditions for intermediate-mass dwarfs, where the observed quenched fractions are the most uncertain. We found that the hot gas halo of dwarf satellites is easy to strip, but the cold ISM is more tenacious, and the conditions for complete stripping depend on the orbital history and feedback strength.
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