A neutral hydrogen study of the galaxy NGC 253.
Abstract
Observations with the 655-foot radio-telescope of the 21-cm hydrogen line of the galaxy NGC 253 yield a H I mass of 7.8 x 106 Me or nearly 6% of the total mass of 1.3 x 1011 Me for a distance of 3.4 Mpc. The integrated H i-contours indicate an asynlmetry in the distribution of neutral hydrogen. There is 30% more neutral hydrogen on one side (5W) of the galaxy than on the other (NE). A deep central depression in the H i-contour map cannot be explained by simple symmetric H i-models; absorption of the emission from the strong central source by the H i in front is suspected. Parameters of the H i-distribution and the rotation curve are deduced by a model4itting procedure. Outside the central region of the galaxy ouly a small velocity dispersion (5-8 km/s) was found. Key words: galaxies - hydrogen
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- March 1972
- Bibcode:
- 1972A&A....17..207H