<i>XMM</i>observations of the high-redshift quasar RX J1028.6 - 0844 at<i>z</i>= 4.276: soft X-ray spectral flattening

Yuan, Weimin; Fabian, A. C.; Celotti, A.; McMahon, R. G.; Matsuoka, M.

doi:10.1111/j.1365-2966.2005.08800.x

Cited by 21 publications

(28 citation statements)

References 35 publications

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“…Due to the capability of the EPIC pn to observe down to low X-ray energies of 0.2 keV, Grupe et al (2004a) measured an intrinsic absorption column N H of at most a few times 10 22 cm À2 . From a 10 times longer XMM-Newton observation Yuan et al (2005) confirmed that, indeed, the source is not as highly absorbed as claimed from the ASCA data; the best-fit intrinsic cold absorption is N H ¼ 2:1 þ0:4 À0:3 ; 10 22 cm À2 . Yuan et al (2005) argue for an additional warm absorber with column density N H > 2 ; 10 22 cm À2 .…”

Section: Pmn J0525à3343supporting

confidence: 77%

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XMM-NewtonObservations of High-Redshift Quasars

et al. 2006

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We report on our XMM-Newton observations of the high-redshift quasars BR 2237À0607 (z ¼ 4:558) and BR 0351À1034 (z ¼ 4:351). We also report on XMM-Newton observations of 19 other z > 4 objects available in the public archive of which 14 were detected. We find that the optical to X-ray spectral index ox is correlated with the luminosity density at 2500 8 but does not show a correlation with redshift, which is consistent with earlier results. Radio-loud quasars are brighter and have flatter X-ray slopes compared to radio-quiet quasars. There is some evidence for the jet-dominated sources to be intrinsically absorbed. The mean intrinsic 2-10 keV power-law slope of the 10 high-redshift radio-quiet quasars in our sample for which a spectral analysis can be performed is X ¼ 1:21 AE 0:52 (ranging between 0.32 and 1.96), which is more like the X ¼ 1:19 AE 0:10 found from the ASCA observations of low-redshift narrow-line Seyfert 1 galaxies (NLS1s) but different from the X ¼ 0:78 AE 0:11 found for lowredshift broad-line Seyfert galaxies. The steep X-ray spectral index suggests high Eddington ratios L/L Edd . These observations give credence to the hypothesis of Mathur that NLS1s are low-luminosity cousins of high-redshift quasars. Comparison with other results from the literature indicates that perhaps the most luminous quasars, from low to high redshift, have similarly steep X-ray spectra suggestive of high Eddington luminosities.

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Section: Pmn J0525à3343supporting

confidence: 77%

“…From a 10 times longer XMM-Newton observation Yuan et al (2005) confirmed that, indeed, the source is not as highly absorbed as claimed from the ASCA data; the best-fit intrinsic cold absorption is N H ¼ 2:1 þ0:4 À0:3 ; 10 22 cm À2 . Yuan et al (2005) argue for an additional warm absorber with column density N H > 2 ; 10 22 cm À2 .…”

Section: Pmn J0525à3343supporting

confidence: 77%

XMM-NewtonObservations of High-Redshift Quasars

et al. 2006

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“…The lower limits shown with a (blue) pentagon and arrow in the 4–5 redshift bin corresponds to the existence of at least four blazars for which we have estimated a black hole mass larger than 10 9 M ⊙ . They are RXJ 1028.6−0844 ( z = 4.276; Yuan et al 2005); GB 1508+5714 ( z = 4.3; Hook et al 1995); PMN J0525−3343 ( z = 4.41; Worsley et al 2004a) and GB 1428+4217 ( z = 4.72; Worsley et al 2004b). There are other three blazars with 4 < z < 5 discussed in Yuan et al (2006), but they have X‐ray luminosities smaller than 10 47 erg s −1 .…”

Section: Discussionmentioning

confidence: 90%

Chasing the heaviest black holes of jetted active galactic nuclei

Ghisellini

Ceca

Volonteri

et al. 2010

Monthly Notices of the Royal Astronomical Society

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We investigate the physical properties of 10 blazars at redshift greater than 2 detected in the 3‐yr all‐sky survey performed by the Burst Alert Telescope (BAT) on board the Swift satellite. We find that the jets of these blazars are among the most powerful known. Furthermore, the mass of their central black hole, inferred from the optical–ultraviolet bump, exceeds a few billions of solar masses, with accretion luminosities being a large fraction of the Eddington one. We compare their properties with those of the brightest blazars of the 3‐month survey performed by the Large Area Telescope (LAT) on board the Fermi satellite. We find that the BAT blazars have more powerful jets, more luminous accretion discs and larger black hole masses than LAT blazars. These findings can be simply understood on the basis of the blazar sequence, which suggests that the most powerful blazars have a spectral energy distribution with a high‐energy peak at MeV (or even sub‐MeV) energies. This implies that the most extreme blazars can be found more efficiently in hard X‐rays, rather than in the high‐energy γ‐ray band. We then discuss the implications of our findings for future missions, such as the New Hard X‐ray Mission (NHXM) and especially the Energetic X‐ray Imaging Survey Telescope (EXIST) mission which, during its planned 2‐yr all‐sky survey, is expected to detect thousands of blazars, with a few of them at z≳ 6.

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“…The observed X-ray variability in both flux and spectrum reported here for Swift J1656.3-3302 is unusual, though not unprecedented in FSRQs. Indeed, a number of other high-z blazars show the same behavior, such as RX J1028.6−0844 (z = 4.2; Yuan et al 2005) and GB B1428+4217 (z = 4.7; Worsley et al 2006) and, in more recent studies, RBS 315 (z = 2.7; Tavecchio et al 2007) and QSO 0836+710 (z = 2.2; Sambruna et al 2007). This variability could be due to changes in the electron distribution at low energies, or may be a hint of the presence of an extra component, which becomes stronger or weaker as the source brightness changes.…”

Section: Discussionmentioning

confidence: 96%

High-redshift blazar identification for Swift J1656.3-3302

Masetti

Mason

Landi

et al. 2008

A&A

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We report on the high-redshift blazar identification of a new gamma-ray source, Swift J1656.3−3302, detected with the BAT imager onboard the Swift satellite and the IBIS instrument on the INTEGRAL satellite. Follow-up optical spectroscopy has allowed us to identify the counterpart as an R ∼ 19 mag source that shows broad Lyman-α, Si iv, He ii, C iv, and C iii] emission lines at redshift z = 2.40 ± 0.01. Spectral evolution is observed in X-rays when the INTEGRAL/IBIS data are compared to the Swift/BAT results, with the spectrum steepening when the source gets fainter. The 0.7-200 keV X-ray continuum, observed with Swift/XRT and INTEGRAL/IBIS, shows the power law shape typical of radio loud (broad emission line) active galactic nuclei (with a photon index Γ ∼ 1.6) and a hint of spectral curvature below ∼2 keV, possibly due to intrinsic absorption (N H ∼ 7× 10 22 cm −2 ) local to the source. Alternatively, a slope change (∆Γ ∼ 1) around 2.7 keV can describe the X-ray spectrum equally well. At this redshift, the observed 20-100 keV luminosity of the source is ∼10 48 erg s −1 (assuming isotropic emission), making Swift J1656.3−3302 one of the most X-ray luminous blazars. This source is yet another example of a distant gamma-ray loud quasar discovered above 20 keV. It is also the farthest object, among the previously unidentified INTEGRAL sources, whose nature has been determined a posteriori through optical spectroscopy.

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XMMobservations of the high-redshift quasar RX J1028.6 - 0844 atz= 4.276: soft X-ray spectral flattening

Cited by 21 publications

References 35 publications

XMM-NewtonObservations of High-Redshift Quasars

XMM-NewtonObservations of High-Redshift Quasars

Chasing the heaviest black holes of jetted active galactic nuclei

High-redshift blazar identification for Swift J1656.3-3302

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