HiObservations of the Local Group Dwarf WLM

We present Australia Telescope Compact Array mosaic H I imaging of the Local Group dwarf irregular galaxy WLM. We find an integrated flux of 149 Jy km s -1 and a total H I mass of (3.2 ± 0.3) × 10 7 M ⊙ . The major axis of the H I is aligned with the stellar component of the galaxy. The overall H I distribution is relatively smooth at our resolution and has a double-peaked central core. One of these peaks is aligned with a region found to have extinction that is internal to WLM, and we take this as possible evidence of a large molecular gas complex in the southern half of the galaxy. The other H I peak is in close proximity to the brightest H II regions. WLM's overall velocity field is consistent with rigid-body rotation. A rotation curve is derived, and we find a total dynamical mass of (3.00 ± 0.80) × 10 8 M ⊙ . We also performed a wide-field search, 38' in radius, for H I companions or evidence of recent interactions (e.g., tidal tails) and found no detections to an H I mass limit of M H I > 8.4 × 10 5 M ⊙ .