Cambridge University Press (CUP), Proceedings of the International Astronomical Union, S244(3), p. 120-126, 2007
DOI: 10.1017/s1743921307013907
Full text: Unavailable
AbstractRecent VLA observations pointed at dwarf spheroidal (dSph) galaxies in the M 81 group reveal a hitherto hidden population of extremely low mass (~ 105 M⊙) HI clouds with no obvious optical counterparts. We have searched 10 fields in the M 81 group totalling 2.2 square degree, both targeting known dwarf spheroidal galaxies and blank fields around the central triplet. Our observations show that the new population of low–mass HI clouds appears to be confined to a region toward the south–east of the central triplet (at distances of ~ 100 kpc from M 81). Possible explanations for these free–floating HI clouds are that they are related to the dSphs found to the South–East of M 81, that they belong to the galaxies of the M 81 triplet (equivalent to HVCs), that they are of primordial nature and provide fresh, unenriched material falling into the M 81 group, or that they are tidal debris from the 3–body interaction involving M 81–M 82–NGC 3077. Based on circumstantial evidence, we currently favour the latter explanation.