Redshifts of the brightest X-ray QSO's
Abstract
The plot of the X-ray luminosity (in 0.5 4.5 KeV band and for Friedmann universe withq 0=+1) of the brightest X-ray QSO at each redshift against redshift shows that the X-ray luminosity increases more or less monotonically with redshift uptoz∼3. This result has been attributed to the selection effect known as the ‘volume effect’. When this selection effect is taken into account in the optical, radio and X-ray windows of the electromagnetic spectrum, a sample of the brightest X-ray QSO's is obtained which shows a small dispersion in X-ray luminosity: <logL χ1>=46.15±0.25. The redshift-X-ray flux density plot for this sample gives slopes of both regression lines which agree, at a confidence level of 95% or greater, with the slopes expected theoretically if the redshifts of the QSO's are cosmological in nature.
- Publication:
-
Astrophysics and Space Science
- Pub Date:
- October 1985
- DOI:
- 10.1007/BF00653831
- Bibcode:
- 1985Ap&SS.115..107S
- Keywords:
-
- Hubble Diagram;
- Quasars;
- Red Shift;
- X Ray Sources;
- Luminosity;
- Regression Analysis;
- Astrophysics