Gravitational redshift of emission lines in the AGN spectra

Bon, N.; Bon, E.; Marziani, Paola; Jovanović, P.

doi:10.1007/s10509-015-2555-5

Cited by 28 publications

(32 citation statements)

References 66 publications

(91 reference statements)

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“…Netzer (1977) created a simple model of a rotating disc with velocity (v) between 5000 and 15 000 km s −1 , with some inclination angles and many radii, assuming gravitational redshift, and obtained line profiles shifted to the red. Further works also analysed the gravitational redshift influence in the AGN emission-line profiles, using more detailed models -see Bon et al (2015) and the references therein.…”

Section: Gravitational Redshiftmentioning

confidence: 99%

NGC 1566: analysis of the nuclear region from optical and near-infrared Integral Field Unit spectroscopy

Silva

Steiner

Menezes

2017

Monthly Notices of the Royal Astronomical Society

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We analysed the centre of NGC 1566, which hosts a well-studied active galactic nucleus (AGN), known for its variability. With the aid of techniques such as Principal Component Analysis Tomography, analysis of the emission-line spectra, channel maps, Penalized Pixel Fitting and spectral synthesis applied to the optical and near-infrared data cubes, besides the analysis of Hubble Space Telescope images, we found that: (1) the AGN has a Seyfert 1 emission, with a very strong featureless continuum that we described as a power law with spectral index of 1.7. However, this emission may come not only from the AGN [as its point spread function (PSF) is broader than the PSF of the broad-line region (BLR)], but from hot and young stars, the same ones that probably account for the observed σ-drop.(2) There is a correlation between redshift and the full width at half-maximum of the BLR emission lines. With a simple model assuming gravitational redshift, we described it as an emitting ring with varying emitting radii and small inclination angles. (3) There is an H ii region close to the AGN, which is composed of many substructures forming an apparent spiral with a velocity gradient. (4) We also detected a probable outflow coming from the AGN and it seems to contaminate the H ii region emission. (5) We identified an H 2 rotating disc with orientation approximately perpendicular to this outflow. This suggests that the rotating disc is an extension of an inner torus/disc structure, which collimates the outflow emission, according to the Unified Model.

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Section: Gravitational Redshiftmentioning

confidence: 99%

NGC 1566: analysis of the nuclear region from optical and near-infrared Integral Field Unit spectroscopy

Silva

Steiner

Menezes

2017

Monthly Notices of the Royal Astronomical Society

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“…Composite spectra of individual spectral types can be modeled by a broad Gaussian component (the BC, symmetric and unshifted, assumed to be the virialized component), and a redshifted very-broad Gaussian component. This latter component presumably associated with "perturbed" virialized motions or gravitational redshift in the inner BLR [74] systematically increases the line width with respect to the BC that provides the VBE.…”

Section: Lils: Hβ and Mgiiλ2800mentioning

confidence: 99%

Quasar Black Hole Mass Estimates from High-Ionization Lines: Breaking a Taboo?

Marziani

Olmo

Martínez-Aldama

et al. 2017

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Abstract:Can high ionization lines such as CIVλ1549 provide useful virial broadening estimators for computing the mass of the supermassive black holes that power the quasar phenomenon? The question has been dismissed by several workers as a rhetorical one because blue-shifted, non-virial emission associated with gas outflows is often prominent in CIVλ1549 line profiles. In this contribution, we first summarize the evidence suggesting that the FWHM of low-ionization lines like Hβ and MgIIλ2800 provide reliable virial broadening estimators over a broad range of luminosity. We confirm that the line widths of CIVλ1549 is not immediately offering a virial broadening estimator equivalent to the width of low-ionization lines. However, capitalizing on the results of Coatman et al. (2016) and Sulentic et al. (2017), we suggest a correction to FWHM CIVλ1549 for Eddington ratio and luminosity effects that, however, remains cumbersome to apply in practice. Intermediate ionization lines (IP ∼ 20-30 eV; AlIIIλ1860 and SiIII]λ1892) may provide a better virial broadening estimator for high redshift quasars, but larger samples are needed to assess their reliability. Ultimately, they may be associated with the broad-line region radius estimated from the photoionization method introduced by Negrete et al. (2013) to obtain black hole mass estimates independent from scaling laws.

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“…It is interesting that current results of all these cases show that the radial velocity curves of the red side of broad emission lines show larger amplitude shift with more significant indication of periodicity, as in case of NGC 3516 [38], where the same effect is observed in red wing of Fe Kα line. However, this is expected, since that the gravitational effects are more significant on the red side of the line due to gravitational redshift effect [39], and it could be seen in magneto hydrodynamic simulations of eccentric SMBBH systems [27].…”

Section: Supermassive Black Hole Binariesmentioning

confidence: 94%

On the Time Scales of Optical Variability of AGN and the Shape of Their Optical Emission Line Profiles

Bon

Marziani

Jovanović

et al. 2019

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The mechanism of the optical variability of active galactic nuclei (AGN) is still very puzzling. It is now widely accepted that the optical variability of AGN is stochastic, producing red noise-like light curves. In case they were to be periodic or quasi-periodic, one should expect that the time scales of optical AGN variability should relate to orbiting time scales of regions inside the accretion disks with temperatures mainly emitting the light in this wavelength range. Knowing the reverberation scales and masses of AGN, expected orbiting time scales are in the order of decades. Unfortunately, most of monitored AGN light curves are not long enough to investigate such time scales of periodicity. Here we investigate the AGN optical variability time scales and their possible connections with the broad emission line shapes.

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Gravitational redshift of emission lines in the AGN spectra

Cited by 28 publications

References 66 publications

NGC 1566: analysis of the nuclear region from optical and near-infrared Integral Field Unit spectroscopy

NGC 1566: analysis of the nuclear region from optical and near-infrared Integral Field Unit spectroscopy

Quasar Black Hole Mass Estimates from High-Ionization Lines: Breaking a Taboo?

On the Time Scales of Optical Variability of AGN and the Shape of Their Optical Emission Line Profiles

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