The environment of active galactic nuclei – I. A two-component broad emission line model

Collin-Souffrin, S.; Dyson, J. E.; McDowell, Jonathan; Perry, J. J.

doi:10.1093/mnras/232.3.539

Cited by 140 publications

(142 citation statements)

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“…In this particular case, an interpretation that is at least qualitatively consistent with all the data and relatively simple is that the Balmer lines arise primarily in material that is in a flattened disk-like configuration at a low inclination (to account for the narrow width of the Hβ line), and the high-ionization lines arise in an outflowing polar wind, of which we see preferentially the component on the near side of the disk (to account for high velocity and blueward asymmetry) (2). If indeed the Hβ emission arises primarily in a low-inclination disk, our virial mass estimate of M = 1.1 × 10 6 M ⊙ might seriously underestimate the black-hole mass.…”

Section: The Virial Mass and Implications For Nls1ssupporting

confidence: 80%

Variability of NGC 4051 and the nature of narrow-line Seyfert 1 galaxies

Peterson

McHardy

Wilkes

2000

New Astronomy Reviews

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We report on a three-year program of coordinated X-ray and optical monitoring of the narrow-line Seyfert 1 galaxy NGC 4051. The rapid continuum variations observed in the X-ray spectra are not detected in the optical, although the X-ray and optical continuum fluxes are correlated on time scales of many weeks and longer. Variations in the flux of the broad Hβ line are found to lag behind the optical continuum variations by approximately 6 days (with an uncertainty of 2-3 days), and combining this with the line width yields a virial mass estimate of ∼ 1.1×10 6 M ⊙ , at the very low end of the distribution of AGN masses measured by line reverberation. Strong variability of He ii λ4686 is also detected, and the response time measured is similar to that of Hβ, but with a much larger uncertainty. The He ii λ4686 line is almost five times broader than Hβ, and it is strongly blueward asymmetric, as are the high-ionization UV lines recorded in archive spectra of NGC 4051. The data are consistent with the Balmer lines arising in a low-inclination (nearly face-on) disklike configuration, and the high-ionization lines arising in an outflowing wind, of which we observe preferentially the near side. During the third year of monitoring, both the X-ray continuum and the He ii λ4686 line went into extremely low states, although the optical continuum and the Hβ broad line were both still present and variable. We suggest that the inner part of the accretion disk may have gone into an advection-dominated state, yielding little radiation from the hotter inner disk.

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Section: The Virial Mass and Implications For Nls1ssupporting

confidence: 80%

Variability of NGC 4051 and the nature of narrow-line Seyfert 1 galaxies

Peterson

McHardy

Wilkes

2000

New Astronomy Reviews

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“…Done & Krolik 1996;Elvis 2000;Ferland et al 2009;Gaskell 2009;Shapovalova et al 2010). Second, there has been considerable discussion of the heating efficiency of the LIL BLR: radiative heating seems too low compared with the observed radiation field, and additional mechanical heating seems to be required (Collin-Souffrin et al 1988;Bottorff & Ferland 2002;Shapovalova et al 2004;Shapovalova et al 2010).…”

Section: Discussionmentioning

confidence: 99%

The origin of the broad line region in active galactic nuclei

Czerny

Hryniewicz

2010

A&A

251

213

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Aims. Although broad emission lines are the most reliable signature of the nuclear activity of a galaxy and the location of the emitting material is well measured by the reverberation method, the physical cause of the formation of the broad line region remains unclear. We attempt to place some constraints on its origin. Methods. We study the properties of the accretion disk underlying the broad line region. Results. We find that the effective temperature at the disk radius corresponding to the location of the broad line region, as inferred from the Hβ line, is universal in all monitored sources and equal to 1000 K. This value is close to the limiting value that permits the existence of the dust. Conclusions. The likely origin of the low ionization part of the broad line region is the strong local dusty wind from the disk. This wind becomes exposed to the irradiation by the central regions when moving higher above the disk surface and subsequently behaves like a failed wind, thus leading to a local mixture of inflow and outflow. This may provide the physical explanation of the turbulence needed both to smooth the line profiles as well as provide additional mechanical heating.

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“…There are observational indications that the BLR emission originates in two components, a disc and a wind component (Collin-Souffrin et al 1988;Wills et al 1993;Leighly & Moore 2004;Richards et al 2011;Kruczek et al 2011). Recently, Baskin et al (2014b) noted that if the BAL gas is located at distances similar to those of the BLR, then it likely contributes to the emission of broad lines.…”

Section: Similar Relations For the Broad Line Region C Iv Emissionmentioning

confidence: 99%

On the origins of C iv absorption profile diversity in broad absorption line quasars

Baskin

Laor

Hamann

2015

Monthly Notices of the Royal Astronomical Society

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There is a large diversity in the C iv broad absorption line (BAL) profile among BAL quasars (BALQs). We quantify this diversity by exploring the distribution of the C iv BAL properties, FWHM, maximum depth of absorption and its velocity shift (v md ), using the SDSS DR7 quasar catalogue. We find the following: (i) Although the median C iv BAL profile in the quasar rest-frame becomes broader and shallower as the UV continuum slope (α UV at 1700-3000Å) gets bluer, the median individual profile in the absorber rest-frame remains identical, and is narrow (FWHM = 3500 km s −1 ) and deep. Only 4 per cent of BALs have FWHM > 10, 000 km s −1 . (ii) As the He ii emission equivalent-width (EW) decreases, the distributions of FWHM and v md extend to larger values, and the median maximum depth increases. These trends are consistent with theoretical models in which softer ionizing continua reduce overionization, and allow radiative acceleration of faster BAL outflows. (iii) As α UV becomes bluer, the distribution of v md extends to larger values. This trend may imply faster outflows at higher latitudes above the accretion disc plane. (iv) For non-BALQs, the C iv emission line decreases with decreasing He ii EW, and becomes more asymmetric and blueshifted. This suggests an increasing relative contribution of emission from the BAL outflow to the C iv emission line as the ionizing spectral energy distribution (SED) gets softer, which is consistent with the increasing fraction of BALQs as the ionizing SED gets softer.

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The environment of active galactic nuclei – I. A two-component broad emission line model

Cited by 140 publications

References 0 publications

Variability of NGC 4051 and the nature of narrow-line Seyfert 1 galaxies

Variability of NGC 4051 and the nature of narrow-line Seyfert 1 galaxies

The origin of the broad line region in active galactic nuclei

On the origins of C iv absorption profile diversity in broad absorption line quasars

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