The nearby dwarf galaxy ESO215-G?009 is
unusual in many respects. It is highly obscured by foreground stars and
dust of the Milky Way, making it diffult to measure its properties in
optical images from ground-based
telescopes. In contrast, its neutral hydrogen
(HI) disk - measured with the Australia Telescope Compact Array (ATCA)
as part of the Local Volume HI Survey (LVHIS) project - is huge,
about 10 times larger than the stellar extent seen in the beautiful Hubble
Space Telescope (HST) color-composite image shown above (Koribalski & Wang,
in prep.). ESO215-G?009 also appears to be one of the most isolated galaxies
known in the Local Volume, which may explain its very high HI mass to light
ratio. While there is plenty of gas, a trigger for vigorous star formation
appears to be missing.
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