A study of the evolution of radio-loud quasars with the aid of lensing
Abstract
We present results from a mini-survey of relatively high redshift (1.4< z<3.6) gravitationally lensed radio-loud quasars observed with the Chandra and XMM-Newton X-ray Observatories. The magnification effect allows us to search for changes in quasar properties such as the accretion process over three orders of magnitude in intrinsic X-ray luminosity; search for changes in the absorbing and ionization properties of intrinsic absorbers; search for a correlation between X-ray variability vs. luminosity; and extend the study of quasar properties to unlensed X-ray flux levels as low as a few x 10^-16 erg s^-1 cm^-2. We present a comparison between the X-ray properties of quasars at redshifts near the peak of their comoving number density, thought to have occurred at z ~ 2, and those before this era. This comparison provides clues as to what caused the dramatic decay of the quasar number density as the Universe expands.
- Publication:
-
35th COSPAR Scientific Assembly
- Pub Date:
- 2004
- Bibcode:
- 2004cosp...35.3283C