scholarly journals Properties of Very Broad Line MgII Radio-Loud and Radio-Quiet Quasars

Galaxies ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 74
Author(s):  
Avinanda Chakraborty ◽  
Anirban Bhattacharjee ◽  
Suchetana Chatterjee
Keyword(s):  
Black Hole ◽  
Broad Line ◽  
Full Width ◽  
Bolometric Luminosity ◽  
Broad Emission ◽  
Optical Continuum ◽  
Broad Emission Line ◽  
Parent Sample ◽  
Dust Distribution ◽  
Line Sample

We perform an analysis of the properties of radio-loud (RL) and radio-quiet (RQ) quasars with MgII broad emission line (i-band magnitude ≤19.1 and z ≤1.9), selected from the parent sample of SDSS DR7 catalogue. For sources with full-width half maxima (FWHM) greater than 15,000 km s−1 (very broad line sample; VBL) we find the radio loud fraction (RLF) to be about 40%. To further investigate this result we compare the bolometric luminosity, optical continuum luminosity, black hole (BH) mass and Eddington ratios of our VBL sample of RL and RQ quasars. Our analysis shows that in our VBL sample space, RL quasars have higher luminosities and BH mass than RQ quasars. The similarity in the distribution of their covering fraction (CF) shows that there is no difference in dust distribution between VBL RL and RQ quasars and hence dust is not affecting our results. We also find that there is no correlation of RL quasar properties with optical continuum luminosity and BH mass.

scholarly journals Spectroscopic properties of radio-loud and radio-quiet quasars

2019 ◽  
Vol 15 (S356) ◽  
pp. 72-76
Author(s):  
Avinanda Chakraborty ◽  
Anirban Bhattacharjee
Keyword(s):  
Emission Line ◽  
Flux Density ◽  
Spectroscopic Properties ◽  
Broad Line ◽  
Bolometric Luminosity ◽  
Broad Emission ◽  
Radio Lobe ◽  
Extended Radio ◽  
Broad Emission Line ◽  
5 Ghz

AbstractSurveys have shown radio-loud (RL) quasars constitute 10%-15% of the total quasar population and rest are radio-quiet (RQ). However, it is unknown if this radio-loud fraction (RLF) remains consistent among different parameter spaces. This study shows that RLF increases for increasing full width half maximum (FWHM) velocity of the Hβ broad emission line (z < 0.75). To analyse the reason, we compared bolometric luminosity of RL and RQ quasars sample which have FWHM of Hβ broad emission line greater than 15000km/s (High Broad Line or HBL) with which have FWHM of Hβ emission line less than 2500km/s (Low Broad Line or LBL). From the distributions we can conclude for the HBL, RQ and RL quasars are peaking separately and RL quasars are having higher values whereas for the LBL the peaks are almost indistinguishable. We predicted selection effects could be the possible reason but to conclude anything more analysis is needed. Then we compared our result with Wills & Brotherton (1995) and have shown that some objects from our sample do not follow the pattern of the logR vs FWHM plot where R is the ratio of 5 GHz radio core flux density with the extended radio lobe flux density.

scholarly journals AGN STORM 2. I. First results: A Change in the Weather of Mrk 817

2021 ◽  
Vol 922 (2) ◽  
pp. 151
Author(s):  
Erin Kara ◽  
Missagh Mehdipour ◽  
Gerard A. Kriss ◽  
Edward M. Cackett ◽  
Nahum Arav ◽  
...  
Keyword(s):  
Accretion Disk ◽  
Monitoring Program ◽  
Broad Line ◽  
X Ray ◽  
Broad Line Region ◽  
Broad Emission ◽  
Line Region ◽  
First Results ◽  
Optical Continuum ◽  
Broad Emission Line

Abstract We present the first results from the ongoing, intensive, multiwavelength monitoring program of the luminous Seyfert 1 galaxy Mrk 817. While this active galactic nucleus was, in part, selected for its historically unobscured nature, we discovered that the X-ray spectrum is highly absorbed, and there are new blueshifted, broad, and narrow UV absorption lines, which suggest that a dust-free, ionized obscurer located at the inner broad-line region partially covers the central source. Despite the obscuration, we measure UV and optical continuum reverberation lags consistent with a centrally illuminated Shakura–Sunyaev thin accretion disk, and measure reverberation lags associated with the optical broad-line region, as expected. However, in the first 55 days of the campaign, when the obscuration was becoming most extreme, we observe a de-coupling of the UV continuum and the UV broad emission-line variability. The correlation recovered in the next 42 days of the campaign, as Mrk 817 entered a less obscured state. The short C iv and Lyα lags suggest that the accretion disk extends beyond the UV broad-line region.

scholarly journals Star Clusters in Quasars: Bloated Stars as Broad Emission Line Clouds

1989 ◽  
Vol 134 ◽  
pp. 137-138
Author(s):  
R. C. Puetter
Keyword(s):  
Black Hole ◽  
Emission Line ◽  
Star Clusters ◽  
Hole Formation ◽  
Line Radiation ◽  
Black Hole Formation ◽  
Broad Emission ◽  
Broad Emission Line

Many scenarios of the evolution of star clusters in the centers of galaxies involve the formation of a central supermassive object. Since black hole formation is not 100% efficient in mass usage, stars are left over. This paper investigates the properties of such stars and proposes that their externally heated atmospheres become “bloated” due to radiative forces from trapped line radiation. Such stars would swell to many times their normal diameters and acquire densities, sizes, and mean column masses typical of QSO/AGN emission line clouds (ELCs).

scholarly journals Spectral Variability in Seyfert Galaxies

1987 ◽  
Vol 121 ◽  
pp. 161-167
Author(s):  
B.M. Peterson
Keyword(s):  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Seyfert Galaxies ◽  
Broad Line ◽  
Spectral Variability ◽  
Broad Line Region ◽  
Broad Emission ◽  
Line Region ◽  
Order Of Magnitude ◽  
Optical Continuum

Recent observations of spectral variability in active galactic nuclei have established the connection between the broad emission-line and optical continuum flux changes. The inferred size of the broad-line region is at least an order of magnitude smaller than conventional estimates based on photoionization models, which leads to new conclusions about the nature of the broad-line region.

scholarly journals AGN orientation through the spectroscopic correlations and model of dusty cone shell

2021 ◽  
Author(s):  
M Lakićević ◽  
J Kovačević-Dojčinović ◽  
L Č Popović
Keyword(s):  
Black Hole ◽  
Spectral Properties ◽  
Alternative Explanation ◽  
Selection Effect ◽  
Broad Line ◽  
Black Hole Mass ◽  
Cone Model ◽  
Line Region ◽  
Inclination Angles ◽  
Dust Distribution

Abstract The differences between Narrow Line Seyfert 1 galaxies (NLS1s) and Broad Line AGNs (BLAGNs) are not completely understood; it is thought that they may have different inclinations and/or physical characteristics. The FWHM(Hβ)–luminosities correlations are found for NLS1s and their origin is the matter of debate. Here we investigated the spectroscopic parameters and their correlations considering a dusty, cone model of AGN. We apply a simple conical dust distribution (spreading out of broad line region, BLR), assuming that the observed surface of the model is in a good correlation with MIR emission. The dusty cone model in combination with a BLR provides the possibility to estimate luminosity dependence on the cone inclination. The FWHM(Hβ)–luminosities correlations obtained from model in comparison with observational data show similarities which may indicate the influence of AGN inclination and structure to this correlation. An alternative explanation for FWHM(Hβ)–luminosities correlations is the selection effect by the black hole mass. These FWHM(Hβ)–luminosities correlations may be related to the starburst in AGNs, as well. The distinction between spectral properties of the NLS1s and BLAGNs could be caused by multiple effects: beside physical differencies between NLS1s and BLAGNs (NLS1s have lighter black hole mass than BLAGNs), inclination of the conical AGN geometry may have important role as well, where NLS1s may be seen in lower inclination angles.

scholarly journals The Diversity of Broad Emission-Line Profiles

1997 ◽  
Vol 159 ◽  
pp. 197-198
Author(s):  
Giovanna M. Stirpe ◽  
Andrew Robinson ◽  
David J. Axon
Keyword(s):  
Simple Model ◽  
Emission Line ◽  
Power Law ◽  
Active Galaxies ◽  
Broad Line ◽  
Line Profiles ◽  
Broad Emission ◽  
Power Law Function ◽  
Broad Emission Line ◽  
Almost All

AbstractWe present preliminary results from a study of broad-line profiles in active galaxies. A simple model in which the emissivity is a broken power-law function of radius, and the BLR clouds emit anisotropically, yields very good fits to almost all the Ha profiles in our data base.

scholarly journals Dusty origin of the Broad Line Region in active galaxies

2012 ◽  
Vol 8 (S290) ◽  
pp. 21-24
Author(s):  
Bozena Czerny ◽  
Krzysztof Hryniewicz ◽  
Janusz Kaluzny ◽  
Ishita Maity
Keyword(s):  
Black Hole ◽  
Active Galaxies ◽  
Emission Lines ◽  
Broad Line ◽  
Broad Line Region ◽  
Broad Emission ◽  
Line Region ◽  
Interesting Possibility ◽  
Considerable Complexity

AbstractThe most characteristic property of active galaxies, including quasars, are prominent broad emission lines. I will discuss an interesting possibility that dust is responsible for this phenomenon. The dust is known to be present in quasars in the form of a dusty/molecular torus which results in complexity of the appearance of active galaxies. However, this dust is located further from the black hole than the Broad Line Region. We propose that the dust is present also closer in and it is actually responsible for formation of the broad emission lines. The argument is based on determination of the temperature of the disk atmosphere underlying the Broad Line Region: it is close to 1000 K, independently from the black hole mass and accretion rate of the object. The mechanism is simple and universal but leads to a considerable complexity of the active nucleus surrounding. The understanding the formation of BLR opens a way to use it reliably - in combination with reverberation measurement of its size - as standard candles in cosmology.

scholarly journals THE IMPORTANCE OF BROAD EMISSION LINE WIDTHS IN SINGLE-EPOCH BLACK HOLE MASS ESTIMATES

2012 ◽  
Vol 753 (1) ◽  
pp. L2 ◽  
Author(s):  
R. J. Assef ◽  
S. Frank ◽  
C. J. Grier ◽  
C. S. Kochanek ◽  
K. D. Denney ◽  
...  
Keyword(s):  
Black Hole ◽  
Emission Line ◽  
Black Hole Mass ◽  
Broad Emission ◽  
Line Widths ◽  
Broad Emission Line ◽  
Single Epoch

scholarly journals Spectral variability of the 3C 390.3 nucleus for more than 20 years – II.  Variability of the broad emission-line profiles and He ii λ4686 Å emission-line fluxes

2020 ◽  
Vol 495 (1) ◽  
pp. 971-980
Author(s):  
S G Sergeev
Keyword(s):  
Emission Line ◽  
Emission Region ◽  
Line Profiles ◽  
Broad Emission ◽  
Line Region ◽  
Balmer Lines ◽  
Optical Continuum ◽  
Broad Emission Line ◽  
Disc Configuration ◽  
Factor C

ABSTRACT Results of the analysis of the variability of the H β and H α broad emission-line profiles and the He ii λ4686 Å emission-line fluxes in the 3C 390.3 nucleus during 1992–2014 are present. The observed velocity-dependent lag for the Balmer lines is similar to that expected from the Keplerian disc configuration, although there are some differences. Probably, a radial infall motion can be present in the broad-line region of 3C 390.3 in addition to the Keplerian rotation. The lag of the broad He ii line is 26 ± 8 d, significantly less than that of the Balmer lines, so the He ii emission region is much smaller in size. In terms of the power-law relationship between line and optical continuum fluxes with slowly varying scale factor c(t): $F_{\rm line}\propto c(t)\, F_{\rm cont}^a$, the power a is 1.03 for the broad He ii line, while according to Paper I, the power is equal to 0.77 and 0.54 for the broad H β and H α lines, respectively. It means that the variability amplitude is the largest in the He ii, less in H β, and more less in H α. However, the Balmer lines contain a long-term trend that is not seen in the helium line. The narrow He ii line is variable with the amplitude (max-to-min ratio) Rmax ≈ 3, which is much greater than the variability amplitudes of both the narrow Balmer lines and the narrow [O iii] λ5007 Å line.

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