Issue |
A&A
Volume 411, Number 3, December I 2003
|
|
---|---|---|
Page(s) | 329 - 334 | |
Section | Cosmology (including clusters of galaxies) | |
DOI | https://doi.org/10.1051/0004-6361:20031386 | |
Published online | 17 November 2003 |
The spectrum of the cosmic X-ray background observed by RTXE/PCA
1
Max-Planck-Institute für Astrophysik, Karl-Schwarzschild-Str. 1, 85740 Garching bei München, Germany
2
Space Research Institute, Russian Academy of Sciences, Profsoyuznaya 84/32, 117810 Moscow, Russia
3
Laboratory for High Energy Astrophysics, Code 662, Goddard Space Flight Center, Greenbelt, MD 20771, USA
Corresponding author: M. Revnivtsev, mikej@mpa-garching.mpg.de
Received:
24
June
2003
Accepted:
29
August
2003
We have analyzed a large set of RXTE/PCA
scanning and slewing observations performed between April 1996 and March 1999.
We obtained the 3–20 keV spectrum of the cosmic X-ray background (CXB) by subtracting
Earth-occulted observations from observations of the X-ray sky at high galactic
latitude and far away from sources.
The sky coverage is approximately
~ deg2. The PCA spectrum of CXB in 3–20 keV energy band
is adequately approximated by a single power law with photon index
and normalization at 1 keV
phot/s/cm2/keV/sr.
Instrumental background uncertainty precludes accurate RXTE/PCA
measurements of the spectrum of cosmic X-ray background
at energies above 15 keV and therefore
we cannot detect the high energy cutoff observed by the HEAO-1 A2 experiment.
Deep observations of the 6 high latitude points used to model the PCA background
provide a coarse measure of the spatial
variation of the CXB.
The CXB variations are consistent with a fixed spectral shape and variable normalization
characterized by a fractional rms amplitude of ~7% on angular scales of ~1 square deg.
Key words: cosmology: observations / diffuse radiation / X-rays: general
© ESO, 2003
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