PG1416-129: a Close BALQSO with Low Intrinsic X-Ray Absorption
Abstract
We present a ROSAT X-ray spectrum of the close BALQSO PG1416-129. The spectrum in the ROSAT energy range is found to be well fitted by a power law spectrum with spectral index alpha = -1.2 (0.15), absorbed by the known galactic N_H. The spectral index we find is typical for QSOs, and much steeper than the very flat spectrum found from GINGA observations at higher energies. The combined GINGA/ROSAT spectra fit onto each other well, but show a very sharp break at 3 keV. We derive an upper limit on the internal absorbing column in the BALQSO of N_H < 10(20) cm(-2) if the absorbing matter is cold, and N_H < 5 times 10(20) cm(-2) if the absorbing matter is sufficiently ionized to produce the broad absorption lines. This is considerably smaller than previously derived upper limits on the internal absorption in BALQSOs, which were ~ 10(22) cm(-2) . In combination with the large equivalent width of the BALs observed in PG1461-129, our result significantly constrains the ionization parameter in the BAL clouds and indicates that these clouds can not be very optically thick in the UV resonance lines of CIV and NV.
- Publication:
-
American Astronomical Society Meeting Abstracts
- Pub Date:
- December 1992
- Bibcode:
- 1992AAS...181.1107M