We present results from BeppoSAX observations of 10 low redshift quasars. The quasars are part of the Laor et al. (1997) sample of 23 optically selected PG quasars with redshift < 0.4 and low Galactic absorption along the line of sight. Significant spectral curvature is detected for the 6 quasars with the highest signal to noise ratio in their low energy spectra. The average curvature can be parameterized as a flattening of the underlying power law by Δα ∼ 0.5 above ∼ 1 keV. We find that quasars with a steeper soft X-ray (0.1-2 keV) spectrum tend to be steeper also at higher (2-10keV) energies. The distribution of the best fit 2-10 keV slopes is similar to that found for other radio-quiet AGN and characterized by a large dispersion around the mean: αE ≃ 1.0 ± 0.3. Iron Kα lines are detected in 4 quasars. In the narrow-line quasar PG 1115+407, the rest frame line energy (6.69±0.11 keV) and equivalent width (580±280eV) are consistent with those found in a few low redshift narrow-line Seyfert 1 galaxies (NLSy1). This, together with the similarity of the 0.1-10 keV X-ray continuum, suggests that this quasar is the higher redshift and luminosity analog of a NLSy1. In the broad line quasar PG 0947+396, the rest-frame line energy suggests fluorescence from cold iron. The line equivalent width (> 400 eV) is however about 2-3 times higher than that usually found in Seyfert 1 galaxies. The high energy power-law slopes and the iron line emission properties seem to be unrelated to the X-ray luminosity.
|Original language||English (US)|
|Number of pages||12|
|Journal||Astronomy and Astrophysics|
|State||Published - Dec 1 2000|
All Science Journal Classification (ASJC) codes
- Astronomy and Astrophysics
- Space and Planetary Science