A high-redshift, ultrasoft X-ray AGN.
Abstract
We present ROSAT data for the quasar E 1346 + 266, an AGN identified as part of the Einstein Ultra-Soft Survey, and two other AGN nearby, EX0 1346.4 + 2637 and EX0 1346.2 + 2645. E 1346 + 266 has an unusually high redshift (0.92) for a quasar with a strong, ultrasoft X-ray (0.25 keV) excess. Consequently, the effective restframe temperature of the soft component in E 1346 + 266 is high (blackbody kT_eff_ ~120 eV), and its soft-component luminosity may be the strongest identified in any soft-excess AGN to date. We find that the temperatures and luminosities of bare accretion disc spectra are too low to account for this soft X-ray excess. The addition of a hot, optically thin corona around a geometrically thick disc gives a better agreement with the X-ray data; reprocessing in cool, dense clouds is an alternative. However, published spectra for both models predict an excess of flux in the optical IR relative to the X-rays.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- October 1994
- DOI:
- 10.1093/mnras/270.3.663
- Bibcode:
- 1994MNRAS.270..663P