Issue |
A&A
Volume 403, Number 3, June I 2003
|
|
---|---|---|
Page(s) | 869 - 876 | |
Section | Extragalactic astronomy | |
DOI | https://doi.org/10.1051/0004-6361:20030395 | |
Published online | 23 May 2003 |
On the XMM-Newton spectra of soft X-ray selected QSOs
1
Institute of Astronomy & Astrophysics, National Observatory of Athens, Palaia Penteli, 15236 Athens, Greece
2
Physics Department, University of Athens, Panepistimiopolis, Zografos, 15783 Athens, Greece
3
Instituto de Fisica de Cantabria, CSIC-UC, 39905 Santander, Spain
Corresponding author: I. Georgantopoulos, ig@astro.noa.gr
Received:
31
May
2002
Accepted:
11
March
2003
We study the XMM-Newton spectra of a sample
of 32 soft X-ray selected QSOs.
Our goal is to check, using the spectra
of moderate redshift (),
faint (
)
broad-line QSOs, previous
claims for either significant intrinsic absorption
or spectral hardening at high energies.
We derive hardness ratios
for all sources and furthermore
we perform spectral fits for the 11 brighter sources.
The majority of sources have steep spectra
.
We find a few QSOs with large amounts
of intrinsic absorption, as high as
.
We find no strong evidence for spectral hardening above 2 keV.
The coadded QSO spectrum
is well described by a single power-law
with photon index of ~1.9,
demonstrating that, on average, any effects of absorption
are not important.
This suggests that the discrepancy between the
X-ray background and the (soft X-ray selected) QSO spectrum holds well at the faint fluxes probed here.
Key words: galaxies: active / quasars: general / X-rays: galaxies / X-rays: general
© ESO, 2003
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