CORRELATION ANALYSIS OF A LARGE SAMPLE OF NARROW-LINE SEYFERT 1 GALAXIES: LINKING CENTRAL ENGINE AND HOST PROPERTIES

Variations observed in 5S rRNA base compositions are almost entirely due to fixation of point mutations. As a consequence, 5S rRNA size has remained relatively constant during evolution and, therefore, dependencies among the four bases can be predicted. In order to characterize the nature and to determine the degree of such dependencies, correlation analysis followed by principal component factorial analysis was conducted on a large sample of 5S rRNA sequences. The results show that the purine and pyrimidine contents tend to remain constant, so that A + G = Kpur and C + U = Kpyr. The composition of the four bases expressed now by Kpur/Kpyr relationships is also constant (Ks). These relationships imply that the behavior of the mutations in the variable sites of the molecule follows rules imposed by the chemical nature of the bases involved. Consequently, transition mutations would be more favored than substitutions in transversion sites and also than insertion-deletion (rare in 5S rRNAs), since transitions would not significantly alter the values of the Ks-index.

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Correlation Analysis of Optical and Radio Light Curves for a Large Sample of Active Galactic Nuclei

The Astronomical Journal ◽

10.1086/117540 ◽

1995 ◽

Vol 110 ◽

pp. 529 ◽

Cited By ~ 34

Author(s):

S. D. Clements ◽

A. G. Smith ◽

H. D. Aller ◽

M. F. Aller

Keyword(s):

Correlation Analysis ◽

Active Galactic Nuclei ◽

Galactic Nuclei ◽

Light Curves ◽

Large Sample

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The spatial extension of extended narrow line regions in MaNGA AGN

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz2183 ◽

2019 ◽

Vol 489 (1) ◽

pp. 855-867 ◽

Cited By ~ 2

Author(s):

Jianhang Chen ◽

Yong Shi ◽

Ross Dempsey ◽

David R Law ◽

Yanmei Chen ◽

...

Keyword(s):

Active Galactic Nuclei ◽

Large Distance ◽

Linear Relation ◽

Galactic Nuclei ◽

Narrow Line ◽

High Luminosity ◽

Large Sample ◽

Spatially Resolved ◽

Nearby Galaxies ◽

Log Linear

ABSTRACT In this work, we revisit the size–luminosity relation of the extended narrow line regions (ENLRs) using a large sample of nearby active galactic nuclei (AGNs) from the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey. The ENLRs ionized by the AGN are identified through the spatially resolved BPT diagram, which results in a sample of 152 AGN. By combining our AGN with the literature high-luminosity quasars, we found a tight log-linear relation between the size of the ENLR and the AGN $\rm [O\, III]$λ5007 Å luminosity over four orders of magnitude of the $\rm [O\, III]$ luminosity. The slope of this relation is 0.42 ± 0.02 which can be explained in terms of a distribution of clouds photoionized by the AGN. This relation also indicates that the AGNs have the potential to ionize and heat the gas clouds at a large distance from the nuclei without the aids of outflows and jets for the low-luminosity Seyferts.†

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Emission-line kinematics as a probe of the central engine in QSOs

Symposium - International Astronomical Union ◽

10.1017/s0074180900152921 ◽

1986 ◽

Vol 119 ◽

pp. 331-336

Author(s):

Amri Wandel

Keyword(s):

Energy Source ◽

Emission Line ◽

Dynamic Models ◽

Accretion Rate ◽

Central Mass ◽

Large Sample ◽

Physical Conditions ◽

Central Engine ◽

Central Energy ◽

The Continuum

We investigate the constraints on dynamic models for the line-emitting regions in quasars and AGN. The parameters characterising the central energy source (Mass, efficiency, accretion rate) are calculated in terms of the physical conditions in the line emitting gas. In a large sample the central mass (calculated assuming the emission-line clouds are bound) is proportional to the continuum luminosity. We find typical values of L/LE∼10−2±0.5, e∼0.1-l%, and Ṁ/ṀE∼1–10.

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Correlation space of narrow-line Seyfert 1 galaxies

Proceedings of the International Astronomical Union ◽

10.1017/s1743921312020352 ◽

2012 ◽

Vol 8 (S290) ◽

pp. 349-350

Author(s):

D. W. Xu ◽

S. Komossa

Keyword(s):

Black Hole ◽

Optical Emission ◽

Narrow Line ◽

Close Link ◽

Central Engine ◽

Accretion Rates ◽

Black Hole Growth ◽

Accretion Physics ◽

Correlation Space ◽

Hole Growth

AbstractNarrow-line Seyfert 1 (NLS1) galaxies, as active galactic nuclei with low-mass black holes and high accretion rates, are important targets when addressing questions related to black hole growth and accretion physics. We have studied the correlations among the optical emission-line and continuum properties of a sample of NLS1 galaxies, in comparison with a sample of broad-line Seyfert 1 galaxies. We have shown that the density of the narrow-line region is a key component of Eigenvector 1 space. Density turned out to be as important as the Eddington ratio L/LEdd. This result therefore establishes a close link between central engine and host properties, and places new constraints on host - black hole co-evolution.

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Jetted Narrow-Line Seyfert 1 Galaxies & Co.: Where Do We Stand?

Universe ◽

10.3390/universe6090136 ◽

2020 ◽

Vol 6 (9) ◽

pp. 136

Author(s):

Luigi Foschini

Keyword(s):

Active Galactic Nuclei ◽

Galactic Nuclei ◽

Radio Galaxies ◽

Small Mass ◽

High Energy ◽

Narrow Line ◽

Large Area ◽

Central Engine ◽

Great Performance ◽

Energy Gamma

The discovery in 2008 of high-energy gamma-rays from Narrow-Line Seyfert 1 Galaxies (NLS1s) made it clear that there were active galactic nuclei (AGN) other than blazars and radio galaxies that can eject powerful relativistic jets. In addition to NLS1s, the great performance of the Fermi Large Area Telescope made it possible to discover MeV-GeV photons emitted from more classes of AGN, like Seyferts, Compact Steep Spectrum Gigahertz Peaked Sources (CSS/GPS), and disk-hosted radio galaxies. Although observations indicate a variety of objects, their physical characteristics point to a central engine powered by a relatively small-mass black hole (but, obviously, there are interpretations against this view). This essay critically reviews the literature published on these topics during the last eight years and analyzes the perspectives for the forthcoming years.

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Asymmetric emission of the [OIII]λ5007 profile in narrow-line Seyfert 1 galaxies

Astronomy and Astrophysics ◽

10.1051/0004-6361/201731557 ◽

2018 ◽

Vol 615 ◽

pp. A13 ◽

Cited By ~ 7

Author(s):

E. O. Schmidt ◽

G. A. Oio ◽

D. Ferreiro ◽

L. Vega ◽

W. Weidmann

Keyword(s):

Black Hole ◽

Radial Velocity ◽

Narrow Line ◽

Black Hole Mass ◽

Core Component ◽

Velocity Difference ◽

Narrow Component ◽

The Core ◽

Central Engine ◽

Blue Wing

Context. Many active galactic nuclei (AGN) and particularly narrow-line Seyfert 1 (NLS1) galaxies, usually exhibit blueshifts and blue wings in several emission lines, which are mainly associated with outflows and strong winds. Although there is no clear evidence of the physical origin of the [OIII] blue wings, it has been suggested that they could be emitted from the inner parts of the narrow-line region (NLR). Aims. In order to study the radial velocity difference between the narrow component of Hβ and the core component of [OIII]λ5007 and the asymmetric emission of this forbidden line, we investigate a sample of NLS1 galaxies. One of the aims of this paper is to analyze the blue wings of the [OIII] 5007 profiles and their relation with the central engine. Methods. We have obtained and studied medium-resolution spectra (190 km s−1 FWHM at Hβ) of a sample of 28 NLS1 galaxies in the optical range 4300–5200 Å. We performed Gaussian decomposition to the Hβ and [OIII]λλ 4959,5007 emission profiles in order to study the distinct components of these lines. Results. A new blue outlier galaxy is found, in which the center of the core component of [OIII] is blueshifted by 405 km s−1 relative to the center of the narrow component of Hβ line. We confirmed a previously known correlation between the blueshift and the full width half maximum (FWHM) of the core component of [OIII]λ5007 line. We also corroborated the correlation between the latter and the velocity of the centroid of the blue wing. On the other hand, by studying the radial velocity difference between the blue end of the asymmetric emission and the centroid of the core component of [OIII], we found a correlation between it and the central black hole mass and, therefore, with the luminosity of the broad component of Hβ. Finally, we found a moderate correlation between the luminosity of the [OIII] blue wing and the black hole mass. Conclusions. These results suggest that the asymmetric emission of the [OIII] lines is related to the central engine, not only through the black hole but also in the intensity of the AGN, which is in agreement with previous results.

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Radio-loud narrow-line Seyfert 1 galaxies with high-velocity outflows

Proceedings of the International Astronomical Union ◽

10.1017/s1743921315007498 ◽

2014 ◽

Vol 10 (S312) ◽

pp. 63-65 ◽

Cited By ~ 1

Author(s):

S. Komossa ◽

D. Xu ◽

J. A. Zensus

Keyword(s):

Emission Line ◽

Ionization Potential ◽

High Velocity ◽

Large Scale ◽

Optical Emission ◽

Strong Line ◽

Narrow Line ◽

Line Broadening ◽

Central Engine ◽

Radial Outflow

AbstractWe have studied four radio-loud Narrow-line Seyfert 1 (NLS1) galaxies with extreme optical emission-line shifts, indicating radial outflow velocities of up 2450 km s−1. The shifts are accompanied by strong line broadening, up to 2270 km s−1 in [NeV]. A significant ionization stratification (higher line shift at higher ionization potential) of most ions implies that we see a large-scale wind rather than single, localized jet-cloud interactions. The observations are consistent with a scenario, where the signatures of outflows are maximized because of a pole-on view into the central engine of these radio-loud NLS1 galaxies.

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Microdensitometer—computer correlation analysis of ultrastructural periodicity

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100081024 ◽

1978 ◽

Vol 36 (2) ◽

pp. 32-33

Author(s):

D.R. Ensor ◽

C.G. Jensen ◽

J.A. Fillery ◽

R.J.K. Baker

Keyword(s):

Correlation Analysis ◽

Background Noise ◽

Computer Control ◽

Optical Diffraction ◽

Screw Thread ◽

Straight Line ◽

Computer Storage ◽

Correlation Process ◽

Electron Microscope Image ◽

Fixed Beam

Because periodicity is a major indicator of structural organisation numerous methods have been devised to demonstrate periodicity masked by background “noise” in the electron microscope image (e.g. photographic image reinforcement, Markham et al, 1964; optical diffraction techniques, Horne, 1977; McIntosh,1974). Computer correlation analysis of a densitometer tracing provides another means of minimising "noise". The correlation process uncovers periodic information by cancelling random elements. The technique is easily executed, the results are readily interpreted and the computer removes tedium, lends accuracy and assists in impartiality.A scanning densitometer was adapted to allow computer control of the scan and to give direct computer storage of the data. A photographic transparency of the image to be scanned is mounted on a stage coupled directly to an accurate screw thread driven by a stepping motor. The stage is moved so that the fixed beam of the densitometer (which is directed normal to the transparency) traces a straight line along the structure of interest in the image.

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