University of Hertfordshire

From the same journal

From the same journal

By the same authors


  • Ashkbiz Danehkar
  • Michael A. Nowak
  • Julia C. Lee
  • Gerard A. Kriss
  • Andrew J. Young
  • Martin J. Hardcastle
  • Susmita Chakravorty
  • Taotao Fang
  • Joseph Neilsen
  • Farid Rahoui
  • Randall K. Smith
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Original languageEnglish
Article number165
JournalThe Astrophysical Journal
Publication statusPublished - 2 Feb 2018


We present a detailed X-ray spectral study of the quasar PG 1211+143 based on Chandra High Energy Transmission Grating Spectrometer (HETGS) observations collected in a multi-wavelength campaign with UV data using the Hubble Space Telescope Cosmic Origins Spectrograph (HST-COS) and radio bands using the Jansky Very Large Array (VLA). We constructed a multi-wavelength ionizing spectral energy distribution using these observations and archival infrared data to create xstar photoionization models specific to the PG 1211+143 flux behavior during the epoch of our observations. Our analysis of the Chandra-HETGS spectra yields complex absorption lines from H-like and He-like ions of Ne, Mg, and Si, which confirm the presence of an ultra-fast outflow (UFO) with a velocity of approximately -17,300 km s -1 (outflow redshift z out ∼ -0.0561) in the rest frame of PG 1211+143. This absorber is well described by an ionization parameter and column density. This corresponds to a stable region of the absorber's thermal stability curve, and furthermore its implied neutral hydrogen column is broadly consistent with a broad Lyα absorption line at a mean outflow velocity of approximately -16,980 km s -1 detected by our HST-COS observations. Our findings represent the first simultaneous detection of a UFO in both X-ray and UV observations. Our VLA observations provide evidence for an active jet in PG 1211+143, which may be connected to the X-ray and UV outflows; this possibility can be evaluated using very-long-baseline interferometric observations.


This is an author-created, un-copyedited version of an article published in The Astrophysical Journal. The Version of Record is available online at


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