The Pole of the Galaxy as Determined from Measurements at 205 Mc/sec.
Abstract
The position of the pole of the galaxy was determined from measurements of galactic radiation at a frequency of 205 megacycles per second. The radiation is found to be highly concentrated along a small circle close to the galactic equator. The co-ordinates of the pole are 266?8 + 4?5 galactic longitude and 87?43 + O?34 north galactic latitude, referred to the 1900 I.A.U. pole. The small circle has a north polar distance, 0, of 91?28 + O?18. The characteristics and calibration of the radio telescope employed in these measurements are described. The observational technique and the treatment of the data are presented in detail. There is a discussion of the sources of error in the observations and an analysis of the reliability of the results. Two alternative hypotheses are suggested to explain the serious deviations of 0 from 90 . The first, judged the less likely, would require changing the accepted height of the sun above the galactic plane from 10 or 20 parsecs to a value of several hundred parsecs. The alternative is to disregard the theoretical calculations of the opacity of the galaxy for the radiation at 205 mc which have been made on the basis of currently used formulae representing free-free transitions in the interstellar medium as the sole source of the opacity. An observational value of approximately unity per kiloparsec is derived for the mean absorption coefficient in the plane of the galaxy at 205 mc.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- January 1951
- DOI:
- 10.1086/145374
- Bibcode:
- 1951ApJ...113...21S