A Massive X-Ray Outflow from the Quasar PDS 456

By J. Reeves, P. O’Brien, Martin P. Ward. 2003

163 citations recorded by the source corpus.

We report on XMM-Newton spectroscopic observations of the luminous radio-quiet quasar PDS 456. The hard X-ray spectrum of PDS 456 shows a deep absorption trough (constituting 50% of the continuum) at energies above 7 keV in the quasar rest frame, which can be attributed to a series of blueshifted K-shell absorption edges due to highly ionized iron. The higher resolution soft X-ray Reflection Grating Spectrometer spectrum exhibits a broad absorption line feature near 1 keV, which can be modeled by a blend of L-shell transitions from highly ionized iron (Fe XVII-Fe XXIV). An extreme outflow velocity of ~50,000 km s-1 is required to model the K- and L-shell iron absorption present in the XMM-Newton data. Overall, a large column density (NH = 5 × 1023 cm-2) of highly ionized gas (log ξ = 2.5) is required in PDS 456. A high-mass outflow rate of ~10 M☉ yr-1 (assuming a conservative outflow covering factor of 0.1 sr) is derived, which is of the same order as the overall mass accretion rate in PDS 456. The kinetic energy of the outflow represents a substantial fraction (~10%) of the quasar energy budget, while the large column and outflow velocity place PDS 456 toward the extreme end of the broad absorption line quasar population.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/47558b31dc43faa61c9962b03d6a2e30e39f1100

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In Astronomy and Astrophysics

1. D. M. Alexander
2. C. Harrison
3. A. King
4. A. M. Swinbank
5. James Mullaney
6. N. Nesvadba
7. K. Pounds
8. C. Done

Citations in the corpus

• Kiloparsec-scale outflows are prevalent among luminous AGN: outflows and feedback in the context of the overall AGN population (2014, background): “…has shown that a highfraction, and potentially all, of high-accretion rate AGN drive highvelocity outflows (v ≈ 0.1c) close to their accretion disks (i.e., on sub-parsec scales; e.g., Blustin et al. 2003; Reeves et al. 2003; Ganguly & Brotherton 2008; Tombesi et al. 2010; Gofford et al. 2011).”
• On why the iron K-shell absorption in AGN is not a signature of the local warm/hot intergalactic medium (2008, background): “However, the derived columns ofNH ∼ 1023 cm−2 are high even for an intrinsic AGN outflow (Pounds et al 2003, hereafter P03; Reeves et al 2003).”
• Extreme Gas Kinematics in the z = 2.2 Powerful Radio Galaxy MRC 1138–262: Evidence for Efficient Active Galactic Nucleus Feedback in the Early Universe? (2006, background): “Blueshifted X-ray absorption lines in quasar spectra indeed suggest parsec-scale outflows,withmassloss rates of 1M yr 1 and velocities 0.1c (e.g., Reeves et al. 2003).”
• Evidence of a high-velocity ionized outflow in a second narrow-line quasar PG 0844+349 (2003, background): “Taken together with the evidence reported here (and for PG 1211+143 and PDS456) it seems a reasonable speculation that a high column density and high-velocity (hence massive) outflow may be a common property of luminous AGN.”
• Powerful Outflows and Feedback from Active Galactic Nuclei (2015, background): “A decade after the first reports (Pounds et al. 2003, Reeves et al. 2003), high-velocity (v∼0.1c), highly-ionized winds are now established to be common in low redshift AGN.”