H I in the field of the dwarf Spheroidal/Irregular galaxy Phoenix.
ST-GERMAIN J., CARIGNAN C., COCTE S. and OOSTERLOO T.
Abstract (from CDS):
New results are presented for a mosaic mapping of the H I in the field of the Local Group dwarf galaxy Phoenix. The observations, obtained with the Australia Telescope Compact Array, cover an area of ∼2°x2°. Four velocity components are identified, at heliocentric velocities of -23, 7, 59, and 140 km.s–1. While the gas at 7 km.s–1 is of Galactic origin and the gas at 140 km.s–1 is most likely associated with the Magellanic Stream, the situation for the two other components is unsure. However, it is suggested that the component at -23 km.s–1 is probably associated with Phoenix because: (1) it has a compact structure and is only slightly offset from the optical image, (2) its H I mass of ∼105M☉ is what can be expected in such a system, 3) it has a definite velocity gradient, (4) its location west of Phoenix is compatible with the already suspected self-propagation from east to west of the last star formation episode. Because of the large mass (∼5x106M☉) implied if at the distance of Phoenix and also because of its large extent, the component at +59 km.s–1 is most likely not associated. Optical velocities are still needed to confirm or not those possible associations.
Galaxies: Dwarf - Galaxies: Individual: Name: Phoenix Dwarf - ISM: H I - Galaxies: Local Group - Techniques: Interferometric