scholarly journals Infrared Line Shapes in Active Galactic Nuclei

1994 ◽  
Vol 159 ◽  
pp. 462-462
Author(s):  
Rodger I. Thompson
Keyword(s):  
Active Galactic Nuclei ◽  
Electron Density ◽  
Galactic Nuclei ◽  
Complete Spectrum ◽  
Line Shapes ◽  
Ngc 4151

This paper presents the complete spectrum of NGC 4151 from 0.87 to 2.5 μm as well as detail of the Paschen α profile in 3C273 at a resolution of about 5000. Analysis of the several observed Fe II lines yields a most probable electron density of 104 and a most likely temperature of 104. The Fe II to H ratio is 2+/− 1 × 10−6 which is 5–7% of the available iron if the Fe/H ratio is solar.

AGN evolution as seen in spectral lines: The case of narrow-line Seyfert 1s

2019 ◽  
Vol 15 (S356) ◽  
pp. 94-94
Author(s):  
Marco Berton
Keyword(s):  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Spectroscopic Studies ◽  
Spectral Lines ◽  
Narrow Line ◽  
Line Profiles ◽  
Line Shapes ◽  
Fundamental Information ◽  
Line Region ◽  
Gaussian Samples

AbstractLine profiles can provide fundamental information on the physics of active galactic nuclei (AGN). In the case of narrow-line Seyfert 1 galaxies (NLS1s) this is of particular importance since past studies revealed how their permitted line profiles are well reproduced by a Lorentzian function instead of a Gaussian. This has been explained with different properties of the broad-line region (BLR), which may present more pronounced turbulent motions in NLS1s with respect to other AGN. We investigated the line profiles in a recent large NLS1 sample classified using SDSS, and we divided the sources into two subsamples according to their line shapes, Gaussian or Lorentzian. The line profiles seem to separate all the properties of NLS1s. Black hole mass, Eddington ratio, [OIII] luminosity, and Fe II strength are all very different in the Lorentzian and Gaussian samples, as well as their position on the quasar main sequence. We interpret this in terms of evolution within the class of NLS1s. The Lorentzian sources may be the youngest objects, while Gaussian profiles may be typically associated to more evolved objects. Further detailed spectroscopic studies are needed to fully confirm our hypothesis.

The nature of flux variations in the continua and broad-line regions of selected active galactic nuclei

2020 ◽  
Vol 496 (1) ◽  
pp. 784-800
Author(s):  
A Bewketu Belete ◽  
L J Goicoechea ◽  
B L Canto Martins ◽  
I C Leão ◽  
J R De Medeiros
Keyword(s):  
Active Galactic Nuclei ◽  
Moving Average ◽  
Sampling Rate ◽  
Galactic Nuclei ◽  
Small Sample ◽  
Light Curves ◽  
Ngc 4151 ◽  
The Given ◽  
Ngc 7469 ◽  
The Continuum

ABSTRACT We present a multifractal analysis of the long-term light curves of a small sample of type 1 active galactic nuclei: NGC 4151, Arp 102B, 3C 390.3, E1821+643 and NGC 7469. We aim to investigate how the degrees of multifractality of the continuum and Hβ line vary among the five different objects and to check whether the multifractal behaviours of the continuum and the Hβ line correlate with standard accretion parameters. The backward (θ  = 0) one-dimensional multifractal detrended moving average procedure was applied to light curves covering the full observation period and partial observation periods containing an equal number of epochs for each object. We detected multifractal signatures for the continua of NGC 4151, Arp 102B and 3C 390.3 and for the Hβ lines of NGC 4151 and 3C 390.3. However, we found nearly monofractal signatures for the continua of E1821+643 and NGC 7469, as well as for the Hβ lines of Arp 102B, E1821+643 and NGC 7469. In addition, we did not find any correlations between the degree of multifractality of the Hβ line and accretion parameters, while the degree of multifractality of the continuum seems to correlate with the Eddington ratio (i.e. the smaller the ratio is, the stronger the degree of multifractality). The given method is not robust, and these results should be taken with caution. Future analysis of the sampling rate and other properties of the light curves should help with better constraining and understanding these results.

scholarly journals Fluorescence in the Active Galactic Nuclei NGC 4151

2012 ◽  
Vol 8 (S295) ◽  
pp. 266-266
Author(s):  
Mattias Eriksson ◽  
Hans Veenhuizen
Keyword(s):  
Active Galactic Nuclei ◽  
Wavelength Region ◽  
Galactic Nuclei ◽  
Collisional Excitation ◽  
Ngc 4151 ◽  
Uv Emission

AbstractThe possibility of UV lines from Fe II formed in the BLR of NGC 4151 has been examined. As a result Fe II emission has been shown to play an important role for the topology of the 2000 to 3000 Å wavelength region of the NGC 4151 spectra. The Fe II UV emission originates from two processes, collisional excitation and PAR (photoexcitation by accidental resonance).

Influence of Black Hole Spin on the Shape of the Fe Kα Spectral Line: The Case of 3C 405

2011 ◽  
Vol 20 (3) ◽  
Author(s):  
P. Jovanović ◽  
V. Borka Jovanović ◽  
D. Borka
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Active Galactic Nuclei ◽  
Accretion Disks ◽  
Galactic Nuclei ◽  
Kerr Metric ◽  
Line Shapes ◽  
Cygnus A ◽  
Angular Momenta ◽  
Innermost Region

AbstractHere we analyze how the angular momenta (spins) of black holes in the centers of Active Galactic Nuclei (AGN) affect the shape of the FeK line emitted from their accretion disks. For that purpose, we compared the observed line profile in the case of radio galaxy 3C 405 (Cygnus A) with its profiles, obtained by numerical simulations based on ray-tracing method in the Kerr metric. Our results show that the spins of rotating central black holes of AGN have significant influence on their FeKα line shapes. Also, we found that in the case of Cygnus A the observed line is probably emitted from the innermost region of its slightly inclined accretion disk around very slowly rotating or even stationary central black hole.

scholarly journals X-Ray Properties of Galactic Nuclei

1980 ◽  
Vol 5 ◽  
pp. 623-630
Author(s):  
Daniel W. Weedman
Keyword(s):  
Emission Line ◽  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Seyfert Galaxy ◽  
Seyfert Galaxies ◽  
Strong Emission ◽  
X Ray ◽  
Ngc 4151 ◽  
Survey Results ◽  
Emission Line Galaxies

Preparing this review was my just punishment for stating only two years ago - in another review (Weedman 1977) - that Seyfert galaxies are not strong X-ray sources. I said that because, as recently as three years ago, NGC 4151 was the only Seyfert galaxy known as an X-ray source. Now we have 36 Seyfert 1 galaxies, along with 12 other galaxies with strong emission-line nuclei, that are X-ray sources. And this is all without even having HEAO-2 data at our disposal yet. The study of active galactic nuclei with X-ray astronomy is progressing so rapidly that a reviewer feels almost hopeless. The best I can do is summarize what is known as of the summer of 1979 and give a simple overview of how X-ray and other properties relate.Some excellent reviews of the X-ray properties of Seyfert and other emission-line galaxies already exist. I especially recommend that by Andrew Wilson (1979). He provides very complete references as of a year ago, but X-ray astronomy is progressing so rapidly that he then had only somewhat more than half the active nuclei now in Tables 1 and 2. It was the group working with the Ariel V SSI that made the initial comprehensive X-ray studies of Seyfert galaxies (Ward et al. 1977, Elvis et al. 1978). The UHURU results for Seyfert galaxies followed soon after and are summarized by Tananbaum et al. (1978); the HEAO-A-2 survey results are now in press (Marshall et al. 1979) I have tried to incorporate these and other recent results in Tables 1 and 2.

scholarly journals 1–3-Day Variations of the Broad Emission Lines of Seyfert Nuclei

1987 ◽  
Vol 121 ◽  
pp. 219-222
Author(s):  
Nikolay G. Bochkarev
Keyword(s):  
Active Galactic Nuclei ◽  
Angular Size ◽  
Galactic Nuclei ◽  
Photometric Data ◽  
Emission Lines ◽  
Line Profiles ◽  
Physical Processes ◽  
Ngc 4151 ◽  
Broad Emission ◽  
Broad Emission Line

One of the principal problems of investigation of AGNs is to understand the nature of the central objects and the physical processes which yield their gigantic luminosities. This requires us to consider the innermost parts of AGNs (3–30 gravitational radii, i.e. ≲ 1016 cm: angular size less than 1 milliarcsecond).1–3d variations of the relative shape of broad emission line profiles of active galactic nuclei (AGN) are perhaps the most informative probe of the innermost parts of AGNs (r = 1015–16 cm from the centre). Optimal objects for these observations are Sy 1.5 with strong variations of the non-thermal continuum (e.g. NGC 4151). The expected amplitude of the variations ranges from a few percent to 10–20%. The optimal spectral resolution is 0.5–5 Å. It is very desirable to complement spectral observations with photometric data. The results of the first set of such observations with the 6-meter telescope are reported.

scholarly journals Analyzing temporal variations of AGN emission line profiles in the context of (dusty) cloud structure formation in the broad line region

2019 ◽  
Vol 621 ◽  
pp. A46 ◽  
Author(s):  
J. Esser ◽  
J.-U. Pott ◽  
H. Landt ◽  
W. D. Vacca
Keyword(s):  
Active Galactic Nuclei ◽  
Accretion Disk ◽  
Galactic Nuclei ◽  
Temporal Variations ◽  
Cloud Formation ◽  
Broad Line ◽  
Ngc 4151 ◽  
Broad Line Region ◽  
The Past ◽  
Line Region

The formation processes and the exact appearance of the dust torus and broad line region (BLR) of active galactic nuclei (AGN) are under debate. Theoretical studies show a possible connection between the dust torus and BLR through a common origin in the accretion disk. However observationally the dust torus and BLR are typically studied separately. NGC 4151 is possibly one of the best suited Seyfert 1 galaxies for simultaneous examinations because of its high number of both photometric and spectroscopic observations in the past. Here we compare changes of the dust radius to shape variations of broad emission lines (BEL). While the radius of the dust torus decreased by almost a factor of two from 2004 to 2006 shape variations can be seen in the red wing of BELs of NGC 4151. These simultaneous changes are discussed in a dust and BEL formation scheme. We also use the BEL shape variations to assess possible cloud distributions, especially in azimuthal direction, which could be responsible for the observed variations. Our findings can best be explained in the framework of a dust inflated accretion disk. The changes in the BELs suggest that this dusty cloud formation does not happen continuously, and over the whole accretion disk, but on the contrary in spatially confined areas over rather short amount of times. We derive limits to the azimuthal extension of the observed localized BEL flux enhancement event.

scholarly journals Kinematic signatures of reverberation mapping of close binaries of supermassive black holes in active galactic nuclei

2020 ◽  
Vol 635 ◽  
pp. A1 ◽  
Author(s):  
Andjelka B. Kovačević ◽  
Jian-Min Wang ◽  
Luka Č. Popović
Keyword(s):  
Black Holes ◽  
Active Galactic Nuclei ◽  
Transfer Functions ◽  
Galactic Nuclei ◽  
Supermassive Black Holes ◽  
Close Binary ◽  
Broad Line ◽  
Line Profiles ◽  
Reverberation Mapping ◽  
Line Shapes

Context. An unresolved region in the relative vicinity of the event horizon of a supermassive black holes (SMBH) in active galactic nuclei (AGN) radiates strongly variable optical continuum and broad-line emission flux. These fluxes can be processed into two-dimensional transfer functions (2DTF) of material flows that encrypt various information about these unresolved structures. An intense search for kinematic signatures of reverberation mapping of close binary SMBH (SMBBH) is currently ongoing. Aims. Elliptical SMBBH systems (i.e. both orbits and disc-like broad-line regions (BLR) are elliptic) have not been assessed in 2DTF studies. We aim to numerically infer such a 2DTF because the geometry of the unresolved region is imprinted on their optical emission. Through this, we determine their specific kinematical signatures. Methods. We simulated the geometry and kinematics of SMBBH whose components are on elliptical orbits. Each SMBH had a disc-like elliptical BLR. The SMBHs were active and orbited each other tightly at a subparsec distance. Results. Here we calculate for the first time 2DTF, as defined in the velocity-time delay plane, for several elliptical configurations of SMBBH orbits and their BLRs. We find that these very complex configurations are clearly resolved in maps. These results are distinct from those obtained from circular and disc-wind geometry. We calculate the expected line variability for all SMBBH configurations. We show that the line shapes are influenced by the orbital phase of the SMBBH. Some line profiles resemble observed profiles, but they can also be much deformed to look like those from the disc-wind model. Conclusions. First, our results imply that using our 2DTF, we can detect and quantify kinematic signatures of elliptical SMBBH. Second, the calculated expected line profiles share some intriguing similarities with observed profiles, but also with some profiles that are synthesised in disc-wind models. To overcome the non-uniqueness of the spectral line shapes as markers of SMBBH, they must be accompanied with 2DTF.

scholarly journals 5.9. Gas dynamics in the central part of the Sy 1 galaxies: III Zw 2 and Mrk 817

1998 ◽  
Vol 184 ◽  
pp. 227-228
Author(s):  
L. Č. Popović ◽  
I. Vince ◽  
A. Kubičela ◽  
S. Salim
Keyword(s):  
Active Galactic Nuclei ◽  
Gas Dynamics ◽  
Galactic Nuclei ◽  
Active Galaxies ◽  
Line Shapes

Spectra of Active Galactic Nuclei (AGN) indicate that in their central parts a composite motion of emission gas exists. An analysis of broad as well as narrow lines of active galaxies can give information about gas dynamics in central part of these objects (see e.g. Netzer 1990, Osterbrock 1990). Here we present the investigation of the Hβ and O III[4959,5007] line shapes of the two Sy 1 galaxis: Mrk 817 and III Zw2.

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