Discovery of an Ultraviolet Counterpart to an Ultrafast X-Ray Outflow in the Quasar PG 1211+143

Dec 23, 2017
7 pages
Published in:
  • Astrophys.J. 853 (2018) 2, 166
  • Published: Feb 2, 2018
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Abstract: (IOP)
We observed the quasar PG 1211+143 using the Cosmic Origins Spectrograph on the Hubble Space Telescope in 2015 April as part of a joint campaign with the Chandra X-ray Observatory and the Jansky Very Large Array. Our ultraviolet spectra cover the wavelength range 912–2100 Å. We find a broad absorption feature () at an observed wavelength of 1240 Å. Interpreting this as H i Lyα, in the rest frame of PG 1211+143 (z = 0.0809), this corresponds to an outflow velocity of −16,980 (outflow redshift ), matching the moderate ionization X-ray absorption system detected in our Chandra observation and reported previously by Pounds et al. With a minimum H i column density of , and no absorption in other UV resonance lines, this Lyα absorber is consistent with arising in the same ultrafast outflow as the X-ray absorbing gas. The Lyα feature is weak or absent in archival ultraviolet spectra of PG 1211+143, strongly suggesting that this absorption is transient, and intrinsic to PG 1211+143. Such a simultaneous detection in two independent wavebands for the first time gives strong confirmation of the reality of an ultrafast outflow in an active galactic nucleus.
Note:
  • Accepted for publication in the Astrophysical Journal, 12/23/2017
  • galaxies: active
  • galaxies: individual
  • galaxies: nuclei
  • galaxies: Seyfert