Issue |
Astron. Astrophys. Suppl. Ser.
Volume 120, Number 1, November II 1996
|
|
---|---|---|
Page(s) | 187 - 193 | |
DOI | https://doi.org/10.1051/aas:1996284 | |
Published online | 15 November 1996 |
The energy-dependent temporal variation of the ROSAT PSPC gain
1
Max-Plank-Inst. für extraterrestrische Physik, Germany e-mail: alm@rosat.mpe-garching.mpg.de
2
Astrophysikalisches Institut Potsdam, Germany e-mail: ghasinger@aip.de
3
USRA/Goddard Space Flight Center e-mail: snowden@lheavx.gsfc.nasa.gov
Send offprint request to: M.A. Prieto
Received:
29
August
1995
Accepted:
24
February
1996
The existence of systematic spectral-fit residuals in
ROSAT PSPC spectra, and their dependence on time, is by now a well
established fact. This paper describes how those residuals may
be related to second order variations of the gain of the PSPC as a
function of energy and time. As a result, the energy scale used for the
interpretation of PSPC spectra can be incorrect producing significant
systematic effects, in particular at energies where the effective area
of the instrument changes rapidly. A monotonic gain decay of
per year is measured at 1 keV. A quantitative description of
the PSPC gain-time variation as a function of energy is provided. The
functional dependence of this variation is found to be well
represented by a second order polynomial.
Key words: instrumentation: detectors / methods: data analysis / methods: observational / X-rays: general / space vehicles
© European Southern Observatory (ESO), 1996