New H I Observations of the Prototype Polar Ring Galaxy NGC 4650A
New, high resolution observations of the \hi\ emission line and 20-cm continuum at the Australia Telescope Compact Array (ATCA) for the prototype polar ring galaxy \n4650a\ are presented. We show the presence of a far more extended \hi\ distribution than previously observed with the VLA, and a very regular velocity field out to a distance of ~ 50 kpc. The combined analysis of the \hi\ data with optical and near infrared images argues against previous warp models used to describe the dynamics of this object. A comparison between the high resolution \hi\ images and a new B-band image obtained at the ESO NTT further weakens the interpretation of the optical morphology via warp geometries. The presence of two spiral arms stretching out in the polar disk seems to represent the most likely explanation for the observed morphology and kinematics.
The Astronomical Journal
- Pub Date:
- February 1997