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A brief Chandra observation of the ultraluminous quasar, SDSS J010013.02+280225.8 at redshift 6.326, showed it to be a relatively bright, soft X-ray source with a count rate of about 1 ct/ks. In this paper we present results for the quasar from a 65ks XMM-Newton observation, which well constrains its spectral shape. The quasar is clearly detected with a total of $sim$ 460 net counts in the 0.2-10 keV band. The spectrum is characterised by a simple power-law model with photon index of $Gamma = 2.30^{+0.10}_{-0.10}$, and the intrinsic 2-10 keV luminosity is $3.14times10^{45}$ erg $text{s}^{-1}$. The 1 $sigma$ upper limit to any intrinsic absorption column density is $N_{H} = 6.07times 10^{22} {text{cm}}^{-2}$. No significant iron emission lines were detected. We derive the X-ray-to-optical flux ratio $alpha_{text{ox}}$ of $-1.74pm$0.01, consistent with the values found in other quasars of comparable ultraviolet luminosity. We did not detect significant flux variations either in the XMM-Newton exposure or between XMM-Newton and XMM-Newton observations, which are separated by $sim$ 8 months. The X-ray observation enables the bolometric luminosity to be calculated after modelling the spectral energy distribution: the accretion rate is found to be sub-Eddington.
We report exploratory chandra observation of the ultraluminous quasar SDSS J010013.02+280225.8 at redshift 6.30. The quasar is clearly detected by chandra with a possible component of extended emission. The rest-frame 2-10 keV luminosity is 9.0$^{+9.
Context. X-ray spectral variability analyses of active galactic nuclei (AGN) with moderate luminosities and redshifts typically show a softer when brighter behaviour. Such a trend has rarely been investigated for high-luminosity AGNs ($ L_{bol}gtrsim
(Abridged) We present a spectral analysis of a deep (220 ks) XMM-Newton observation of the Phoenix cluster (SPT-CL J2344-4243), which we also combine with Chandra archival ACIS-I data. We extract CCD and RGS X-ray spectra from the core region to sear
We report on XMM-Newton and optical results for 6 cataclysmic variables that were selected from Sloan Digital Sky Survey spectra because they showed strong HeII emission lines, indicative of being candidates for containing white dwarfs with strong ma
We report on an XMM-Newton observation of the z=1.055 quasar and Giga-hertz Peaked Spectrum (GPS) source 3C 287. Our 62.3 ksec observation provides an exceptional X-ray view of a prominent member of this important subclass of active galactic nuclei (