High resolution observations of M51 at 21 and 49 cm.
Abstract
Recent observations of M 51 at 21 cm and at 49 cm with the Westerbork Synthesis Radio Telescope are presented. The spectral index (21-49) is determined for a large part of the galaxy, and it is found to be characteristically 0.65 in the nuclear region, 0.7 across the disk, and 0.8 in the outer parts. The continuum radiation has about the same extent as the optical radiation on very-long-exposure photographs and the 21-cm line radiation. Some features which are detected in the faint outer structure are suggestive of a continuation of a spiral arm. Peaks along the arms are found to be about 1.3 kpc apart and roughly symmetrically located with respect to the nucleus. The arms/disk contrast is determined to be typically 1.7.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- February 1977
- Bibcode:
- 1977A&A....54..703S
- Keywords:
-
- Galactic Radiation;
- Radio Galaxies;
- Spiral Galaxies;
- Astronomical Maps;
- Continuous Radiation;
- Galactic Structure;
- High Resolution;
- Astronomy