Abstract
We systematically analyse all publicly available XMM-Newton spectra of radio-quiet PG quasars. The soft X-ray excess in these objects is well modelled by an additional, cool, Compton scattering region. However, the remarkably constant temperature derived for this component over the whole sample requires a puzzling fine tuning of the parameters. Instead, we propose that the soft excess is an artifact of strong, relativistically smeared, partially ionized absorption. The strong jump in opacity at ∼0.7 keV from O VII, O VIII and iron can lead to an apparent soft excess below this energy, which is trivially constant since it depends on atomic processes. This can have a dramatic effect on the derived spectrum, which has implications for fitting the relativistic smearing of the reflected iron line emission from the disc.
| Original language | English |
|---|---|
| Pages (from-to) | L7-L11 |
| Number of pages | 5 |
| Journal | Monthly Notices of the Royal Astronomical Society |
| Volume | 349 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - 21 Mar 2004 |
Keywords
- Accretion, accretion discs
- Atomic processes
- X-rays: galaxies
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science