Radiative Transfer and Acceleration in Magnetocentrifugal Winds

Everett, J. E.

doi:10.1086/432678

Cited by 180 publications

(214 citation statements)

References 46 publications

(61 reference statements)

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“…However, the characterization of disk-wind models as generating ''equatorial'' outflows is perhaps taken too literally; the lines of sight closest to the accretion disk are likely completely blocked by the hot dust that obscures the inner accretion region in type 2 (narrowline) quasars and generates the mid-infrared emission. Furthermore, radiatively driven winds are radial with the inclination angle of the outflow dependent on the launching radius: winds launched from closer to the black hole have a smaller inclination angle with respect to the disk normal (Proga et al 2000;Everett 2005). Therefore, even in the disk-wind paradigm where limb-darkening and orientation-dependent attenuation are operating, it is unclear that the inclination angles of BAL and non-BAL quasars would be sufficiently different to detect a mid-infrared excess with the data in hand.…”

Section: Discussionmentioning

confidence: 99%

Radio through X‐Ray Spectral Energy Distributions of 38 Broad Absorption Line Quasars

Gallagher

Hines

Blaylock

et al. 2007

ApJ

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We have compiled the largest sample of multiwavelength spectral energy distributions (SEDs) of broad absorption line (BAL) quasars to date, from the radio to the X-ray. We present new Spitzer MIPS (24, 70, and 160 m) observations of 38 BAL quasars in addition to data from the literature and public archives. In general, the mid-infrared properties of BAL quasars are consistent with those of non-BAL quasars of comparable luminosity. In particular, the optical to mid-infrared luminosity ratios of the two populations are indistinguishable. We also measure or place upper limits on the contribution of star formation to the far-infrared power. Of 22 (57%) upper limits, seven quasars have sufficiently sensitive constraints to conclude that star formation likely contributes little (<20%) to their far-infrared power. The 17 BAL quasars (45%) with detected excess far-infrared emission likely host hyperluminous starbursts with L FIR; SF ¼ 10 13 Y10 14 L . Mid-infrared through X-ray composite BAL quasar SEDs are presented, incorporating all of the available photometry. Overall, we find no compelling evidence for inherent differences between the SEDs of BAL versus non-BAL quasars of comparable luminosity. Therefore a ''cocoon'' picture of a typical BAL quasar outflow whereby the wind covers a large fraction of the sky is not supported by the mid-infrared SED comparison with normal quasars, and the disk-wind paradigm with a typical radio-quiet quasar hosting a BAL region remains viable.

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Section: Discussionmentioning

confidence: 99%

Radio through X‐Ray Spectral Energy Distributions of 38 Broad Absorption Line Quasars

Gallagher

Hines

Blaylock

et al. 2007

ApJ

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“…Moreover, while the existence of the v max YkL k (3000 8) envelope indicates the importance of radiation pressure in driving the BAL outflow, this is not the only possible mechanism. Magnetically driven (e.g., Everett 2005) and thermally driven (e.g., Krolik & Kriss 2001) winds may explain some fraction of BALs with smaller observed values of v max .…”

Section: Radiatively Driven Winds?mentioning

confidence: 99%

Outflows and the Physical Properties of Quasars

Ganguly

Brotherton

Cales

et al. 2007

ApJ

129

147

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We have investigated a sample of 5088 quasars from the SDSS DR2 in order to determine how the frequency and properties of BALs depend on black hole mass, bolometric luminosity, Eddington fraction (L/L Edd ), and spectral slope. We focus only on high-ionization BALs and find a number of significant results. While quasars accreting near the Eddington limit are more likely to show BALs than lower L/L Edd systems, BALs are present in quasars accreting at only a few percent Eddington. We find a stronger effect with bolometric luminosity, such that the most luminous quasars are more likely to show BALs. There is an additional effect, previously known, that BAL quasars are redder on average than unabsorbed quasars. The strongest effects involving the quasar physical properties and BAL properties are related to terminal outflow velocity. Maximum observed outflow velocities increase with both the bolometric luminosity and the blueness of the spectral slope, suggesting that the ultraviolet luminosity to a great extent determines the acceleration. These results support the idea of outflow acceleration via ultraviolet line scattering.

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“…Arav, Li & Begelman 1994;Murray et al 1995;Proga, Stone & Kallman 2000), radiation pressure on dust (Voit, Weymann & Korista 1993;Scoville & Norman 1995), MHD outflows (e.g. Königl & Kartje 1994;Everett 2005;Fukumura et al 2010), or a combination of e.g. magnetic and radiation pressure (de Kool & Begelman 1995).…”

Section: Introductionmentioning

confidence: 99%

Radiation pressure confinement – IV. Application to broad absorption line outflows

Baskin

Laor

Stern

2014

Monthly Notices of the Royal Astronomical Society

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A fraction of quasars present broad absorption lines, produced by outflowing gas with typical velocities of 3000-10,000 km s −1 . If the outflowing gas fills a significant fraction of the volume where it resides, then it will be highly ionized by the quasar due to its low density, and will not produce the observed UV absorption. The suggestion that the outflow is shielded from the ionizing radiation was excluded by recent observations. The remaining solution is a dense outflow with a filling factor f < 10 −3 . What produces such a small f ? Here we point out that radiation pressure confinement (RPC) inevitably leads to gas compression and the formation of dense thin gas sheets/filaments, with a large gradient in density and ionization along the line of sight. The total column of ionized dustless gas is a few times 10 22 cm −2 , consistent with the observed X-ray absorption and detectable P v absorption. The predicted maximal columns of various ions show a small dependence on the system parameters, and can be used to test the validity of RPC as a solution for the overionization problem. The ionization structure of the outflow implies that if the outflow is radiatively driven, then broad absorption line quasars should have L/L Edd 0.1.

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Radiative Transfer and Acceleration in Magnetocentrifugal Winds

Cited by 180 publications

References 46 publications

Radio through X‐Ray Spectral Energy Distributions of 38 Broad Absorption Line Quasars

Radio through X‐Ray Spectral Energy Distributions of 38 Broad Absorption Line Quasars

Outflows and the Physical Properties of Quasars

Radiation pressure confinement – IV. Application to broad absorption line outflows

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