X-Ray Study of the Distant QSO PKS 0237-233 with ASCA and ROSAT
Abstract
The X-ray spectrum of the distant QSO PKS 0237-233 (z=2.223) has been studied with ASCA and ROSAT. The spectrum in the energy range 0.1 keV to 8 keV in the observer's frame is well fitted by a power-law model with a photon index of 1.54+/-0.06 absorbed by the galactic interstellar matter. The lack of excess absorption confirms that such absorption is not a universal property of the high-redshift GHz-peaked spectrum (GPS) sources. From a comparison of the Lyman alpha and the metal absorption lines in the optical and UV bands, small amount of X-ray absorption constrains the ionization state of the metal line system at z=1.65 as [H I/H]>2.5\times 10^{-4} and [C IV/C]>0.11 if the metal line systems have a metal abundance of 0.1ZO .
- Publication:
-
Publications of the Astronomical Society of Japan
- Pub Date:
- February 1998
- DOI:
- 10.1093/pasj/50.1.19
- Bibcode:
- 1998PASJ...50...19Y
- Keywords:
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- GALAXIES: INTERGALACTIC MEDIUM;
- QUASARS;
- X-RAYS: SOURCES