The first XMM-Newton spectrum of a high redshift quasar - PKS 0537-286

Abstract

Abstract. We present XMM-Newton observations of the high redshift (z = 3.104), radio-loud quasar PKS 0537−286. The EPIC CCD cameras provide the highest signal-to-noise spectrum of a high-z quasar to date. The EPIC observations show that PKS 0537−286 is extremely X-ray luminous (LX = 2 10 47 erg s −1 ), with an unusually hard X-ray spectrum (Γ = 1.27± 0.02). The flat power-law emission extends over the whole observed energy range (0.4 to 40 keV in the quasar rest frame); there is no evidence of intrinsic absorption, which has been claimed in PKS 0537−286 and other high z quasars. However, there is evidence for weak Compton reflection. A redshifted iron K line, observed at 1.5 keV -corresponding to ∼6.15 keV in the quasar rest frame -is detected at 95% confidence. If confirmed, this is the most distant iron K line known. The line equivalent width is small (33 eV), consistent with the "X-ray Baldwin effect" observed in other luminous quasars. The reflected continuum is also weak (R ∼ < 0.25). We find the overall spectral energy distribution of PKS 0537−286 is dominated by the X-ray emission, which, together with the flat power-law and weak reflection features, suggests that the X-radiation from PKS 0537−286 is dominated by inverse Compton emission associated with a face-on relativistic jet.

PKS 0537-286, carrying the information of the environment of SMBHs in the early Universe

“…Our reanalysis of the observation in 1999 (orbit 51) confirms the results reported by Reeves et al (2001), where a simple power-law model fits the spectrum to a spectral index Γ = 1.22 ± 0.08 with χ 2 (d.o.f.) = 983(808).…”

“…First we have checked the consistency of the single X-ray spectra among the 3 EPIC detectors within the single observations by fitting power-law model as in Reeves et al (2001). Our reanalysis of the observation in 1999 (orbit 51) confirms the results reported by Reeves et al (2001), where a simple power-law model fits the spectrum to a spectral index Γ = 1.22 ± 0.08 with χ 2 (d.o.f.)…”

“…We further analyzed the XMM-Newton data of PKS 0537-286 observed during orbit 51 (but with latest response) in 1999 and reproduce the fit results as reported in Reeves et al (2001). Explanation of columns: (1) = instruments; (2) = observation date; (3) = fit model; (4) = column density (units of 10 22 cm −2 ), (5) = spectral index; (6) = normalization (units of 10 −4 ph keV −1 cm −2 ); (7) = flux units are 10 −12 erg cm −2 s −1 for all instruments.…”

XMM–Newtonobservations of the Seyfert 1 galaxy ESO 141–G55

“…Orbital motion deep in a relativistic gravitational potential seems to be the probable interpretation for Fe K lines profiles that have been observed to be several tens of thousands of km s −1 broad and significantly redshifted (Mushotzky et al 1995;Tanaka et al 1995;Page et al 2001;Wilms et al 2001;Gondoin et al 2002). Many AGNs show narrow Fe K lines (Gondoin et al 2001a,b;Reeves et al 2001a;Yaqoob et al 2001). Also, a unique iron K emission line profile with two distinct components has been recently reported on Mrk 205 (Reeves et al 2001b).…”

${XMM{-}Newton}$ observations of the Seyfert 1 galaxy NGC 3227

“…Orbital motion deep in a relativistic gravitational potential seems to be the only interpretation for line profiles of that sort. Other AGNs show narrow Fe K lines (Reeves et al 2001a;Yaqoob et al 2001;Gondoin et al 2001a,b). Also, a unique iron K emission line profile with two distinct components has been recently reported (Reeves et al 2001b) in Mrk 205.…”