Further Observations of the Nuclear Rotation in M31
Abstract
Radial-velocity observations of the nucleus of M31 obtained with the Lallemand electronic camera and 120-inch coude spectrograph and with the prime-focus nebular spectrograph are presented. These observations cover the radial distance range (r) from 0 to 24 sec of arc and show that the rotation curve, which has its maximum amplitude in P.A. equals 52 deg, increases linearly from zero at r equals 0 to 104 km per sec at r equals 1.9 sec of arc, beyond which it drops approximately as inversely to the square root of r. After making approximate correction for the effect of seeing and instrumental resolution, we find the radius of the nucleus r equals 1.55 sec of arc or 5.2 pc, a rotational period of 310,000 years, and a mass of 0.16 billion solar masses.
- Publication:
-
Publications of the Astronomical Society of the Pacific
- Pub Date:
- December 1974
- DOI:
- 10.1086/129686
- Bibcode:
- 1974PASP...86..861W
- Keywords:
-
- Andromeda Galaxy;
- Astronomical Spectroscopy;
- Galactic Nuclei;
- Galactic Rotation;
- Radial Velocity;
- Cameras;
- Electronic Control;
- Spectral Resolution;
- Tables (Data);
- Astrophysics