The Gas Content and Stripping of Local Group Dwarf Galaxies

The gas content of the complete compilation Local Group dwarf galaxies (119 within 2 Mpc) is presented using HI survey data. Within virial radius Milky Way (224 kpc here), 53 55 are devoid to limits M$_{\rm HI}<10^4$ M$_\odot$. M31 (266 kpc), 27 30 (with typically $<10^5$ M$_\odot$). Beyond radii and M31, majority have detected masses higher than limits. When relationship between distance investigated a radius, more non-detected this (85$\pm1$ 93 galaxies) M31. Using Gaia proper motion measurements available for 38 galaxies, minimum density required completely strip them calculated. Halo densities $10^{-5}$ $5 \times 10^{-4}$ cm$^{-3}$ instantaneous stripping at perigalacticon. compared halo with expectations from simulations observations, 80% motions consistent being stripped by ram pressure pericenter. results suggest diffuse gaseous galactic medium important in quenching that also potentially plays role.