Volume 490, Number 3, November II 2008
|Page(s)||989 - 994|
|Published online||17 September 2008|
Q2237+0305 in X-rays: spectra and variability with XMM-Newton*
Astronomical Observatory of Kyiv Shevchenko University, Observatorna St. 3, Kiev, UA- 04053, Ukraine e-mail: email@example.com; firstname.lastname@example.org
2 Dipartimento di Astronomia, Università di Bologna, via Ranzani 1, 40127 Bologna, Italy e-mail: [cristian.vignali;giorgio.palumbo]@unibo.it
Accepted: 23 August 2008
Aims. X-ray observations of gravitationally lensed quasars may allow us to probe the inner structure of the central engine of a quasar. Observations of Q2237+0305 (Einstein Cross) in X-rays may be used to constrain the inner structure of the X-ray emitting source.
Methods. Here we analyze the XMM-Newton observation of the quasar in the gravitational lens system Q2237+0305 taken during 2002. Combined spectra of the four images of the quasar in this system were extracted and modelled with a power-law model. Statistical analysis was used to test the variability of the total flux.
Results. The total X-ray flux from all the images of this quadruple gravitational lens system is erg/(cm2 s) in the range 0.2–10 keV, showing no significant X-ray spectral variability during almost 42 ks of the observation time. Fitting of the cleaned source spectrum yields a photon power-law index of . The X-ray lightcurves obtained after background subtraction are compatible with the hypothesis of a stationary flux from the source.
Key words: gravitational lensing / X-rays: general / galaxies: quasars: general
© ESO, 2008
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