Dwarf galaxies in the Local Group
Overview
We have used a new, improved version of the H Ⅰ Parkes All-Sky Survey to search for H Ⅰ emission from nine new, ultrafaint Milky Way satellite galaxy candidates recently discovered in data from the Dark Energy Survey. None of the candidates is detected in H Ⅰ, implying upper limits for their H Ⅰ masses of typically several hundred to a few thousand solar masses. The resulting upper limits on MH Ⅰ / LV (Fig. 1) and MH Ⅰ / M★ suggest that at least some of the new galaxy candidates are H Ⅰ-deficient. This finding is consistent with the general H Ⅰ deficiency of satellite galaxies located within the Milky Way’s virial radius and supports the hypothesis that gas is being removed from satellites by tidal and ram-pressure forces during perigalactic passages. In addition, some of the objects may be embedded in, and interacting with, the extended neutral and ionized gas filaments of the Magellanic Stream.
Publication