The stellar coronal component of the Galaxy. II. an analysis of the stellar content of the Einstein Extended Medium Sensitivity Survey.
Abstract
We present a detailed analysis of the stellar content of the Einstein Extended Medium Sensitivity Survey (EMSS). The analysis consists of a comparison between the observed source counts and expectations computed on the basis of the known X-ray luminosity functions for disk population stars and established models for the structure of the Galaxy. We show that the presence of an excess of X-ray luminous "yellow" stars, already found with the analysis of the stellar content of the Einstein Medium Sensitivity Survey (MSS), is confirmed by the EMSS, whose substantially larger size sample allows to draw conclusions with a higher statistical significance than the MSS, and discuss the nature of this stellar population. Additionally, we show that to ensure the coherence between the observed number of dwarf M stars in the EMSS with the X-ray luminosity functions derived from optically selected sample, it is necessary to take into account the effects deriving from the variation of X-ray luminosity with stellar age, as well as the effect of stellar multiplicity.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- April 1995
- Bibcode:
- 1995A&A...296..370S
- Keywords:
-
- GALAXY: HALO;
- GALAXY: STELLAR CONTENT;
- X-RAYS: STARS;
- STARS: STATISTICS