The Ultra-Fast Outflow of the Quasar PG1211+143
as Viewed by Time-Averaged Chandra Grating Spectroscopy

Ashkbiz Danehkar,
Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA

Michael A. Nowak,
Massachusetts Institute of Technology, Kavli Institute for Astrophysics, Cambridge, MA 02139, USA

Julia C. Lee,
Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA
Harvard John A. Paulson School of Engineering and Applied Science, 29 Oxford Street, Cambridge, MA 02138 USA

Gerard A. Kriss,
Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD, 21218, USA

Andrew J. Young,
University of Bristol, H. H. Wills Physics Laboratory, Tyndall Avenue, Bristol BS8 1TL, UK

Martin J. Hardcastle,
University of Hertfordshire, School of Physics, Astronomy and Mathematics, Hatfield, Hertfordshire AL10 9AB, UK

Susmita Chakravorty,
Department of Physics, Indian Institute of Science, Bangalore 560012, India

Taotao Fang,
Xiamen University, Institute for Theoretical Physics and Astrophysics, Department of Astronomy, Xiamen, Fujian 361005, China

Joseph Neilsen,
Villanova University, Mendel Hall, Room 263A, 800 E. Lancaster Avenue, Villanova, PA 19085, USA

Farid Rahoui,
European Southern Observatory, Karl Schwarzschild-Straße 2, D-85748 Garching bei München, Germany

Randall K. Smith
Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138, USA

Date: Received 2017 October 17; revised 2017 December 14; accepted 2017 December 18; published 2018 February 2

Abstract:

We present a detailed X-ray spectral study of the quasar PG1211+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 PG1211+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 $\sim-$17300 kms$^{-1}$ (outflow redshift $z_{\rm out}\sim -0.0561$) in the rest frame of PG1211+143. This absorber is well described by an ionization parameter $\log \xi \sim2.9$ ergs$^{-1}$cm and column density $\log N_{\rm H} \sim21.5$ cm$^{-2}$. 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 Ly$\alpha$ absorption line at a mean outflow velocity of $\sim -16\,980$ kms$^{-1}$ 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 PG1211+143, which may be connected to the X-ray and UV outflows; this possibility can be evaluated using very-long-baseline interferometric observations.
 
Keywords: quasars: absorption lines -- quasars: individual (PG1211+143 ) -- galaxies: active -- galaxies: Seyfert -- X-rays: galaxies
 
Journal Reference: A. Danehkar, M. A. Nowak, J. C. Lee, G. A. Kriss, A. J. Young, M. J. Hardcastle, S. Chakravorty, T. Fang, J. Neilsen, F. Rahoui, and R. K. Smith. The Astrophysical Journal, 853(2):165, 2018. doi:10.3847/1538-4357/aaa427