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arXiv · 1712.07118

The Ultra-Fast Outflow of the Quasar PG 1211+143 as Viewed by Time-Averaged Chandra Grating Spectroscopy

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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Abstract

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 ~ $-$17,300 km s$^{-1}$ (outflow redshift $z_{\rm out}$ ~ $-$0.0561) in the rest frame of PG 1211+143. This absorber is well described by an ionization parameter $\log ξ$ ~ 2.9 erg s$^{-1}$ cm and column density $\log N_{\rm H}$ ~ 21.5 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$α$ absorption line at a mean outflow velocity of ~ $-$16,980 km s$^{-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 (VLBI) observations.

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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. 2018-02-03. The Ultra-Fast Outflow of the Quasar PG 1211+143 as Viewed by Time-Averaged Chandra Grating Spectroscopy. https://doi.org/10.3847/1538-4357%2Faaa427

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