scholarly journals A search of new samples of active galactic nuclei with low-mass black holes from SDSS

2014 ◽  
Vol 10 (S312) ◽  
pp. 75-76
Author(s):  
H. Liu ◽  
W. Yuan ◽  
H. Zhou ◽  
X.-B. Dong
Keyword(s):  
Black Holes ◽  
Active Galactic Nuclei ◽  
Line Width ◽  
Galactic Nuclei ◽  
Emission Lines ◽  
Broad Line ◽  
Galaxy Sample ◽  
Low Mass ◽  
The Masses ◽  
Larger Sample

AbstractWe report on the progress of our on-going work to search for low-mass black holes (LMBHs) in active galactic nuclei. The masses of black holes are estimated using the broad line width and luminosity obtained from one-epoch optical spectra. As the first step, we fitted the spectra of 1263 objects in the quasar catalog of the SDSS DR10 and obtained accurate measurement of the emission lines. Two AGNs are found to have MBH ~ 106 M⊙. The next step is to analyze the spectra of the DR10 galaxy sample, from which a much larger sample of low-mass AGNs is expected to be obtained.

SDSS J154751.94+025550 with double-peaked broad H β but single-peaked broad H α: a candidate for central binary black hole system?

2021 ◽  
Vol 507 (4) ◽  
pp. 5205-5213
Author(s):  
XueGuang Zhang
Keyword(s):  
Black Hole ◽  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Emission Lines ◽  
Broad Line ◽  
Line Profiles ◽  
Physical Conditions ◽  
Binary Black Hole ◽  
Sinusoidal Function

ABSTRACT In this manuscript, an interesting blue active galactic nuclei (AGNs) SDSS J154751.94+025550 (=SDSS J1547) is reported with very different line profiles of broad Balmer emission lines: double-peaked broad H β but single-peaked broad H α. SDSS J1547 is the first AGN with detailed discussions on very different line profiles of the broad Balmer emission lines, besides the simply mentioned different broad lines in the candidate for a binary black hole (BBH) system in SDSS J0159+0105. The very different line profiles of the broad Balmer emission lines can be well explained by different physical conditions to two central BLRs in a central BBH system in SDSS J1547. Furthermore, the long-term light curve from CSS can be well described by a sinusoidal function with a periodicity about 2159 d, providing further evidence to support the expected central BBH system in SDSS J1547. Therefore, it is interesting to treat different line profiles of broad Balmer emission lines as intrinsic indicators of central BBH systems in broad line AGN. Under assumptions of BBH systems, 0.125 per cent of broad-line AGN can be expected to have very different line profiles of broad Balmer emission lines. Future study on more broad line AGN with very different line profiles of broad Balmer emission lines could provide further clues on the different line profiles of broad Balmer emission lines as indicator of BBH systems.

A Photo-Ionization Method for Black Hole Mass Estimation in Quasars

2011 ◽  
Vol 20 (3) ◽  
Author(s):  
Paola Marziani ◽  
C. Alenka Negrete ◽  
Deborah Dultzin ◽  
Jack W. Sulentic
Keyword(s):  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Compact Object ◽  
Broad Line ◽  
Line Profiles ◽  
Line Broadening ◽  
Physical Conditions ◽  
Ionization Method ◽  
The Masses ◽  
Photo Ionization

AbstractDetermining the masses of the central compact object believed to power all active galactic nuclei is relevant to our understanding of their evolution and of their inner workings. Keys to present-day mass estimates are: (1) the assumption of line broadening due to virial motion of the emitting gas, (2) an estimate of the distance of broad-line emitting gas from the central compact object, and (3) a measure of the AGN luminosity. We discuss the merits and the limitations of an alternative method based on estimates of physical conditions in the broad line emitting region derived from an appropriate multi-component analysis of emission line profiles. This ‘photo-ionization method’, applied to UV intermediate-ionization lines appears to be promising for at least a sizable population of high-z quasars.

Double-peaked emission lines as a probe of the broad-line regions of active galactic nuclei

2009 ◽  
Vol 53 (7-10) ◽  
pp. 133-139 ◽  
Author(s):  
Michael Eracleous ◽  
Karen T. Lewis ◽  
Hélène M.L.G. Flohic
Keyword(s):  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Emission Lines ◽  
Broad Line

scholarly journals FeII, FeI Emission Lines from Accretion Disks: An Explanation for “FeII Problem” in AGNs?

1994 ◽  
Vol 159 ◽  
pp. 463-463
Author(s):  
Chunyan Wei ◽  
Fuzhen Cheng ◽  
Junhan You
Keyword(s):  
Active Galactic Nuclei ◽  
Accretion Disk ◽  
Accretion Disks ◽  
Galactic Nuclei ◽  
Emission Lines ◽  
Broad Line ◽  
Broad Line Region ◽  
Line Region

For the solution of the puzzling “FeII problem” in active galactic nuclei(AGNs) (Netzer et al. 1983; Wills et al. 1985), we pay our attention to optical band and suggest: (1)the observed so-called “FeII emission lines” features may be blending of FeII multiples and FeI multiples. Our previous work(Wei et al. 1993) has showed that there are many FeI emission lines whose wavelength lie around the observed “FeII emission lines” features. In fact, FeI emission lines have been observed in the spectrum of PHL 1092(Bergeron et al. 1980; Cheng et al. 1993). (2)the emission lines from accretion disk must be considered besides the emission from broad line region.

scholarly journals The AGN-Starburst Connection traced by the Nitrogen Abundance

2012 ◽  
Vol 8 (S290) ◽  
pp. 273-274
Author(s):  
Kenta Matsuoka ◽  
Tohru Nagao ◽  
Alessandro Marconi ◽  
Roberto Maiolino ◽  
Yoshiaki Taniguchi
Keyword(s):  
Black Holes ◽  
Star Formation ◽  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Emission Lines ◽  
Agb Stars ◽  
Line Flux ◽  
Quasar Spectra ◽  
Star Formation Activity ◽  
Nitrogen Abundance

AbstractThe connection between the active galactic nuclei (AGNs) and star formation activity is one of the most important issues in understanding the coevolution of supermassive black holes (SMBHs) and galaxies. In our recent study, by using SDSS quasar spectra we found that the emission-line flux rations involving a nitrogen line correlate with the Eddington ratio. This correlation suggests that the mass accretion in quasars is associated with a post-starburst phase, when AGB stars enrich the interstellar medium with the nitrogen. Moreover, we focused on nitrogen-loud quasars, that have prominent emission lines of the nitrogen, to investigate whether this argument is correct. In this symposium, we present our results regarding the relation between the star formation and feeding to SMBHs traced by the nitrogen abundance.

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