Q2237+0305 in X-rays: spectra and variability with XMM-Newton

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 6 × 10 −13 erg/(cm 2 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 Γ= 1.82 +0.07 −0.08 . The X-ray lightcurves obtained after background subtraction are compatible with the hypothesis of a stationary flux from the source.

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