Accretion Disk Winds from Active Galactic Nuclei

Murray, Norman; Chiang, J.; Grossman, Scott A.; Voit, G. Mark

doi:10.1086/176238

Cited by 822 publications

(1,106 citation statements)

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“…12 for a possible structure). Given the small scales implied for this absorber as well as the requisite column density, this absorber could be identified with the '' hitchhiking gas '' proposed by Murray et al (1995), which shields the BAL wind from becoming completely ionized by extreme ultraviolet and soft X-ray photons. The hitchhiking gas would not contribute a reflected continuum because it is so highly ionized, although it could scatter X-rays into the line of sight.…”

Section: X-ray Variability and Spectral Resultsmentioning

confidence: 88%

“…The smallest possible source of a reflecting medium would be the BAL wind (e.g., Elvis 2000) at distances typical of the broad-line region (e.g., Ogle 1998). Even if the BAL wind resides at the smallest radii modeled (R $ 10 16 cm; e.g., Murray et al 1995), however, the shortest expected timescale of variability for the reflected continuum would be days to weeks, as opposed to the hours observed. Therefore, even assuming the smallest reasonable scale for reflecting material, a reflection-dominated continuum is not favored by our observation of hard-band variability.…”

Section: X-ray Variability and Spectral Resultsmentioning

confidence: 93%

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X‐Raying the Ultraluminous Infrared Starburst Galaxy and Broad Absorption Line QSO Markarian 231 withChandra

Gallagher

Brandt

Chartas

et al. 2002

ApJ

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With 40 ks of Chandra ACIS-S3 exposure, new information on both the starburst and QSO components of the X-ray emission of Markarian 231, an ultraluminous infrared galaxy and broad absorption line QSO, has been obtained. The bulk of the X-ray luminosity is emitted from an unresolved nuclear point source, and the spectrum is remarkably hard, with the majority of the flux emitted above 2 keV. Most notably, significant nuclear variability (a decrease of $45% in approximately 6 hr) at energies above 2 keV indicates that Chandra has probed within light-hours of the central black hole. Although we concur with Maloney & Reynolds that the direct continuum is not observed, this variability coupled with the 188 eV upper limit on the equivalent width of the Fe K emission line argues against the reflection-dominated model put forth by these authors based on their ASCA data. Instead, we favor a model in which a small, Compton-thick absorber blocks the direct X-rays, and only indirect, scattered X-rays from multiple lines of sight can reach the observer. Extended soft, thermal emission encompasses the optical extent of the galaxy and exhibits resolved structure. An off-nuclear X-ray source with a 0.35-8.0 keV luminosity of L X ¼ 7 Â 10 39 ergs s À1 , consistent with the ultraluminous X-ray sources in other nearby starbursts, is detected. We also present an unpublished Faint Object Spectrograph spectrum from the Hubble Space Telescope archive showing the broad C iv absorption.

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Section: X-ray Variability and Spectral Resultsmentioning

confidence: 88%

Section: X-ray Variability and Spectral Resultsmentioning

confidence: 93%

X‐Raying the Ultraluminous Infrared Starburst Galaxy and Broad Absorption Line QSO Markarian 231 withChandra

Gallagher

Brandt

Chartas

et al. 2002

ApJ

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“…Proga et al 2000;Murray et al 1995;Filiz Ak et al 2013). There exists an empirical relation between the BLR size and the continuum luminosity in AGN/QSOs (e.g.…”

Section: Introductionmentioning

confidence: 99%

Variability of QSOs with variable regions in broad absorption troughs from the Sloan Digital Sky Survey

He¹,

Bian²,

Ge³

et al. 2015

Mon. Not. R. Astron. Soc.

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The variability of broad absorption lines is investigated for a sample of 188 broad-absorptionline (BAL) quasars (QSOs) (z > 1.7) with at least two-epoch observations from the Sloan Digital Sky Survey Data Release 7 (SDSS DR7), covering a time-scale of about 0.001 -3 years in the rest frame. Considering only the longest time-scale between epochs for each QSO, 73 variable regions in the C IV BAL troughs are detected for 43 BAL QSOs. The proportion of BAL QSOs showing variable regions increases with longer time-interval than about 1 year in the rest frame. The velocity width of variable regions is narrow compared to the BALtrough outflow velocity. For 43 BAL QSOs with variable regions, it is found that there is a medium strong correlation between the variation of the continuum luminosity at 1500 Å and the variation of the spectral index. With respect to the total 188 QSOs, larger proportion of BAL QSOs with variable regions appears bluer during their brighter phases, which implies that the origin of BAL variable regions is related to the central accretion process. For 43 BAL QSOs with variable regions, it is possible that there is a negative medium strong correlation between the absolute variation of the equivalent width and the Mg II -based black hole mass, and a medium strong correlation between the maximum outflow velocity of variable regions and the Eddington ratio. These results imply the connection between the BAL-trough variation and the central accretion process.

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“…Such wind would be ubiquitous in AGN but only visible when the gas crosses our line of sight (Goodrich & Miller 1995;Hines & Wills 1995;Murray et al 1995;Elvis 2000;. It has also been suggested that the same gas may be responsible for absorption and emission (e.g., Mathur et al 1995;Elvis 2000;Fields et al 2005;Krongold et al 2007;Andrade-Velazquez et al 2010;Longinotti et al 2013;Miniutti et al 2014;Sanfrutos et al 2016), or that BALs may be associated to the obscuring dusty torus (Leighly et al 2015).…”

Section: Introductionmentioning

confidence: 94%

Hubble Space Telescope observations of BALQSO Ton 34 reveal a connection between the broad-line region and the BAL outflow

Krongold¹,

Binette²,

Bohlin³

et al. 2017

Monthly Notices of the Royal Astronomical Society

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Ton 34 recently transitioned from non-absorbing quasar into a BALQSO.Here, we report new HST-STIS observations of this quasar. Along with CIV absorption, we also detect absorption by NV+Lyα and possibly O VI+Lyβ. We follow the evolution of the CIV BAL, and find that, for the slower outflowing material, the absorption trough varies little (if at all) on a rest-frame timescale of ∼ 2 yr. However, we detect a strong deepening of the absorption in the gas moving at larger velocities (−20, 000 -−23, 000 km s −1 ). The data is consistent with a multistreaming flow crossing our line of sight to the source. The transverse velocity of the flow should be ∼ few thousand km s −1 , similar to the rotation velocity of the BLR gas (≈ 2, 600 km s −1 ). By simply assuming Keplerian motion, these two components must have similar locations, pointing to a common outflow forming the BLR and the BAL. We speculate that BALs, mini-BALs, and NALs, are part of a common, ubiquitous, accretion-disk outflow in AGN, but become observable depending on the viewing angle towards the flow. The absorption troughs suggests a wind covering only ∼20 % of the emitting source, implying a maximum size of 10 −3 pc for the clouds forming the BAL/BLR medium. This is consistent with constraints of the BLR clouds from X-ray occultations. Finally, we suggest that the low excitation broad emission lines detected in the spectra of this source lie beyond the wind, and this gas is probably excited by the shock of the BAL wind with the surrounding medium.

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Accretion Disk Winds from Active Galactic Nuclei

Cited by 822 publications

References 0 publications

X‐Raying the Ultraluminous Infrared Starburst Galaxy and Broad Absorption Line QSO Markarian 231 withChandra

X‐Raying the Ultraluminous Infrared Starburst Galaxy and Broad Absorption Line QSO Markarian 231 withChandra

Variability of QSOs with variable regions in broad absorption troughs from the Sloan Digital Sky Survey

Hubble Space Telescope observations of BALQSO Ton 34 reveal a connection between the broad-line region and the BAL outflow

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