2020MNRAS.495.2652L -
Mon. Not. R. Astron. Soc., 495, 2652-2663 (2020/July-1)
X-ray observations of luminous dusty quasars at z > 2.
LANSBURY G.B., BANERJI M., FABIAN A.C. and TEMPLE M.J.
Abstract (from CDS):
We present new X-ray observations of luminous heavily dust-reddened quasars (HRQs) selected from infrared (IR) sky surveys. HRQs appear to be a dominant population at high redshifts and the highest luminosities, and may be associated with a transitional 'blowout' phase of black hole and galaxy co-evolution models. Despite this, their high-energy properties have been poorly known. We use the overall sample of 10 objects with XMM-Newton coverage to study the high-energy properties of HRQs at <Lbol>=1047.5 erg s–1 and <z>=2.5. For seven sources with strong X-ray detections, we perform spectral analyses. These find a median X-ray luminosity of <L_ 2-10 keV_ >= 1045.1 erg s–1, comparable to the most powerful X-ray quasars known. The gas column densities are NH = (1-8) x 1022 cm–2, in agreement with the amount of dust extinction observed. The dust-to-gas ratios are sub-Galactic, but are higher than found in local AGN. The intrinsic X-ray luminosities of HRQs are weak compared to the mid-IR (L_ 6 µm_) and bolometric luminosities (Lbol), in agreement with findings for other luminous quasar samples. For instance, the X-ray to bolometric corrections range from κbol ≃ 50 to 3000. The moderate absorption levels and accretion rates close to the Eddington limit (<λEdd>=1.06) are in agreement with a quasar blowout phase. Indeed, we find that the HRQs lie in the forbidden region of the NH-λEdd plane, and therefore that radiation pressure feedback on the dusty interstellar medium may be driving a phase of blowout that has been ongoing for a few 105 yr. The wider properties, including [O III] narrow-line region kinematics, broadly agree with this interpretation.
Abstract Copyright:
© 2020 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society
Journal keyword(s):
galaxies: active - galaxies: evolution - galaxies: nuclei - quasars: general - X-rays: galaxies
CDS comments:
p.2659: J1117 and J1303 not identified (not enough information, probable misprints).
Simbad objects:
16
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