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

TL;DR

This study analyzes XMM-Newton X-ray observations of the gravitationally lensed quasar Q2237+0305, finding stable flux and spectral properties over a 42 ks observation, providing insights into the quasar's inner structure.

Contribution

First detailed X-ray spectral and variability analysis of Q2237+0305 using XMM-Newton data, constraining the quasar's inner X-ray emitting region.

Findings

Total X-ray flux is 6 x 10^{-13} erg/cm2/s with no significant variability.

Spectral photon index is approximately 1.82, indicating a typical quasar X-ray spectrum.

Flux remains stationary over the observation period.

Abstract

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. 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. The total X-ray flux from all the images of this quadruple gravitational lens system is 6 x 10^{-13} 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 Gamma=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.