Quasar H  profiles and discs

Jackson, N.; Penston, M. V.; Pérez, E.

doi:10.1093/mnras/249.4.577

Cited by 13 publications

(11 citation statements)

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“…The timescale to change the geometry of these systems (r out /r in and/or inclination) is much longer than the observed timescale of line profile variability, disfavoring geometrical changes as the cause of the observed variability. The line profile variability of these objects is uncorrelated with variability of the observed continuum flux of the source, in contradiction with predictions by Jackson et al (1991). Another issue with the third suggested explanation is that single-peaked lines are very difficult to produce in this scenario, which would lead to a higher fraction of double-peaked emitters than observed in the AGN population.…”

Section: Introductioncontrasting

confidence: 59%

“…A few explanations for the rare occurrence of DPEL have been suggested in the context of the scenario of line production in the accretion disk: (1) geometrical reasons: large r out /r in (Dumont & Collin-Souffrin 1990) and/or small inclination (Corbin 1997), (2) radiative transfer effects through a disk wind (Chiang & Murray 1996;Murray & Chiang 1997, hereafter CM96 and MC97, respectively), (3) the geometry of the ionizing source and the scattering medium (Jackson et al 1991), and (4) an additional BLR zone outside of the disk (Popović et al 2004;Bon et al 2009). A more detailed summary and discussion of these ideas can be found in Eracleous & Halpern (2003).…”

Section: Introductionmentioning

confidence: 99%

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Effects of an Accretion Disk Wind on the Profile of the Balmer Emission Lines From Active Galactic Nuclei

Flohic¹,

Eracleous²,

Bogdanović³

2012

ApJ

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We explore the connection between active galactic nuclei (AGNs) with single-and double-peaked broad Balmer emission lines by using models dealing with radiative transfer effects through a disk wind. Our primary goal is to assess the applicability of the Murray & Chiang model by making an extensive and systematic comparison of the model predictions with data. In the process, we also verify the original derivation and evaluate the importance of general relativistic effects. As the optical depth through the emission layer increases, the peaks of a double-peaked profile move closer and eventually merge, producing a single peak. The properties of the emission line profile depend as sensitively on the geometric parameters of the line-emitting portion of the disk as they do on the diskwind parameters. Using a parameter range that encompasses the expected characteristics of the broad-line regions in AGNs, we construct a database of model profiles and measure a set of diagnostic properties. Comparisons of the model profiles with emission lines from a subset of Sloan digital Sky Survey quasars show that observed lines are consistent with moderately large optical depth in the disk wind and a range of disk inclinations i 45• . Including relativistic effects is necessary to produce the asymmetries of observed line profiles.

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Section: Introductioncontrasting

confidence: 59%

Section: Introductionmentioning

confidence: 99%

Effects of an Accretion Disk Wind on the Profile of the Balmer Emission Lines From Active Galactic Nuclei

Flohic¹,

Eracleous²,

Bogdanović³

2012

ApJ

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“…Instead of asking why a few percent of AGNs show double-peaked emission lines, we ask why most AGNs do not show double-peaked emission lines, since virtually all AGNs must have accretion disks. Possible reasons include: i) a vertical extended ionizing structure is required for double-peaked emitters , so if there is no illuminating source shining on the disk, the double-peaked lines will either disappear or be weak and buried on the continuum, or ii) if the disk extends to large radius (Rokaki et al 1992;Jackson et al 1991), iii) the disk is face-on or iv) there is a disk wind (Murray & Chiang 1997;Eracleous et al 2004). Any of the above could smear out the double-peaked profile.…”

Section: Discussionmentioning

confidence: 99%

The Quasar SDSS J153636.22+044127.0: A Double-Peaked Emitter in a Candidate Binary Black Hole System

Tang¹,

Grindlay²

2009

ApJ

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Double-peaked emission lines are believed to be originated from accretion disks around supermassive black holes (SMBHs), and about 3% of z < 0.33 AGNs are found to be double-peaked emitters. The quasar SDSS J153636.22+044127.0 has recently been identified with peculiar broad-line emission systems exhibiting multiple redshifts. We decompose the Hα and Hβ profiles into a circular Keplerian disk line component and other Gaussian components. We propose that the system is both a doublepeaked emitter and a binary SMBH system, where the extra-flux in the blue peaks of the broad lines comes from the region around the secondary black hole. We suggest that such black hole binary systems might also exist in many known double-peaked emitters, where the tidal torques from the secondary black hole clear the outer region of the disk around the primary black hole, similar to the gap in a protostellar disk due to the process of planetary migration, and might also stimulate the formation of a vertical extended source in the inner region around the primary which illuminates the disk. However, most secondary SMBHs in such systems might be too small to maintain a detectable broad line region (BLR), so that the disk line from the primary dominates.

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“…The line-emitting disk in most AGNs could be quite large with a ratio of outer to inner radius of order 10 or more. This would bring the two peaks of a double-peaked line close together and make the profiles appear single-peaked (Dumont & Collin-Souffrin 1990a;Jackson, Penston, & Pérez 1991).…”

Section: Connection Of Double-peaked Emitters With Thementioning

confidence: 99%

Completion of a Survey and Detailed Study of Double‐peaked Emission Lines in Radio‐loud Active Galactic Nuclei

Eracleous

Halpern

2003

ApJ

232

246

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We report the completion of a survey of radio-loud active galactic nuclei (AGNs) begun in an earlier paper with the main goal of finding and studying broad, double-peaked Balmer lines. We present Hα spectra of 13 more broad-lined objects, including 3 with double-peaked Hα profiles. The final sample includes 106 radio-loud AGNs. In our final census 20% of objects have Hα lines with double peaks or twin shoulders (the "double-peaked emitters") and of these, 60% (the disk-like emitters) can be fitted quite well with a model attributing the emission to a circular, relativistic, Keplerian disk. In four objects where broad Hβ and Mg ii lines have been observed, we compare the profiles with models of photoionized accretion disks and find them to be in reasonable agreement. We reaffirm the conclusion of paper I that double-peaked emitters stand out among radio-loud AGNs on the basis of a number of additional properties that they possess: (i) an unusually large contribution of starlight to the optical continuum around Hα, (ii) unusually large equivalent widths of low-ionization lines ([O i] and [S ii]), (iii) unusually large [O i]/[O iii] ratios, and (iv) Balmer lines which are on average twice as broad as those of other radio-loud AGNs and preferentially redshifted. We consider and evaluate models for the origin of the lines and we find accretion-disk emission to be the most successful one because it can explain the double-peaked line profiles and it also offers an interpretation of the additional spectroscopic properties of these objects. We find the alternative suggestions (binary broad-line regions, bipolar outflows, anisotropically illuminated spherical broad-line regions) unsatisfactory because (a) they fail direct observational tests, (b) they cannot explain all of the unusual properties of disk-like emitters self-consistently, or (c) in one case the physical foundations appear to be unsound. We suggest that double-peaked emitters and accretion-powered LINERs are the segment of the AGN population in which the accretion rate is considerably lower than the Eddington rate, with the consequence that the inner accretion disk takes the form of an ion torus and the wind that normally enshrouds the disk proper is absent.

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Quasar H profiles and discs

Cited by 13 publications

References 0 publications

Effects of an Accretion Disk Wind on the Profile of the Balmer Emission Lines From Active Galactic Nuclei

Effects of an Accretion Disk Wind on the Profile of the Balmer Emission Lines From Active Galactic Nuclei

The Quasar SDSS J153636.22+044127.0: A Double-Peaked Emitter in a Candidate Binary Black Hole System

Completion of a Survey and Detailed Study of Double‐peaked Emission Lines in Radio‐loud Active Galactic Nuclei

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