Cospatial Counterrotating Stellar Disks in the Virgo E7/S0 Galaxy NGC 4550
Abstract
We have discovered two cospatial stellar disks, one orbiting prograde, one orbiting retrograde, in NGC 4550, an E7/S0 galaxy in the core of the Virgo Cluster. One of the stellar disks is coincident with a gas disk. Absorption and emission-line velocities for the two counterrotating components have been measured over about one-third of the optical diameter (30"). We propose that after the initial stellar disk of NGC 4550 was formed, a substantial amount of counterrotating gas was acquired >= 10^9^ yr ago. It then settled to the plane via dissipation; the bulk of the counterrotating stars most likely formed after the gas settled to the plane.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- July 1992
- DOI:
- 10.1086/186460
- Bibcode:
- 1992ApJ...394L...9R
- Keywords:
-
- Counter Rotation;
- Elliptical Galaxies;
- Stellar Structure;
- Absorption Spectra;
- Astronomical Spectroscopy;
- Emission Spectra;
- Galactic Structure;
- Luminosity;
- Virgo Galactic Cluster;
- Astrophysics;
- GALAXIES: CLUSTERING;
- GALAXIES: ELLIPTICAL AND LENTICULAR;
- CD;
- GALAXIES: KINEMATICS AND DYNAMICS