New HI Observations of the prototype Polar Ring Galaxy NGC 4650A
Abstract
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 NGC 4650A are presented. They 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 (NIR) images argues against previous warp models used to describe the dynamics of this object. Further analysis of the new B-band image obtained at the European Southern Observatories New Technology Telescope (NTT) indicates clearly that the polar structure extends continuously to within about 200 pc of the nucleus of the central host galaxy, ruling out the presence of a `hole' in the central region of this component. 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.
- Publication:
-
Publications of the Astronomical Society of Australia
- Pub Date:
- April 1997
- DOI:
- 10.1071/AS97092
- Bibcode:
- 1997PASA...14...92A
- Keywords:
-
- GALAXIES;
- INDIVIDUAL (NGC 4650A);
- KINEMATICS & DYNAMICS;
- DARK MATTER;
- galaxies: individual (NGC 4650A);
- galaxies: kinematic and dynamics;
- dark matter