scholarly journals THE BALDWIN EFFECT IN THE NARROW EMISSION LINES OF ACTIVE GALACTIC NUCLEI

2012 ◽  
Vol 762 (1) ◽  
pp. 51 ◽  
Author(s):  
Kai Zhang ◽  
Ting-Gui Wang ◽  
C. Martin Gaskell ◽  
Xiao-Bo Dong
Keyword(s):  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Emission Lines ◽  
Baldwin Effect ◽  
The Baldwin Effect ◽  
Narrow Emission

scholarly journals Composite Models: A Tool for Interpreting the Emission-Line Spectra of Active Galactic Nuclei

1989 ◽  
Vol 134 ◽  
pp. 316-317
Author(s):  
S.M. Viegas-Aldrovandi ◽  
M. Contini
Keyword(s):  
Energy Source ◽  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Emission Lines ◽  
Additional Energy ◽  
Physical Conditions ◽  
Dilute Gas ◽  
Composite Models ◽  
Line Widths ◽  
Narrow Emission

In the last decade, emission-lines from a large number of active galactic nuclei (AGN) have been observed. Most of the models built to explain the observed narrow emission-lines are based on photoionization. Although these photoionization models account for the observed general features, many points remain unexplained and several authors suggest an additional energy source (Ferland and Mushotzky 1984, Ferland and Osterbrock 1986, Stasinska 1984, Viegas-Aldrovandi and Gruenwald 1988). Another possible explanation is suggested by the emitting cloud motions, which account for the observed line widths. If the clouds are moving throughout a dilute gas (n0 ≃ 300 cm−3), a shock can develop. Then, the physical conditions in the cloud are determined by the coupled effect of photoionization and shock hydrodynamics.

scholarly journals Evidence of AGN-driven Outflows in Young Radio Quasars Selected from the Wide-field Infrared Survey Explorer

2013 ◽  
Vol 9 (S304) ◽  
pp. 347-348
Author(s):  
Minjin Kim ◽  
Luis C. Ho ◽  
Carol J. Lonsdale ◽  
Mark Lacy ◽  
Andrew W. Blain ◽  
...  
Keyword(s):  
Active Galactic Nuclei ◽  
Near Infrared ◽  
Galactic Nuclei ◽  
Emission Lines ◽  
Wide Field ◽  
Near Infrared Spectra ◽  
Sky Survey ◽  
Line Widths ◽  
Infrared Survey ◽  
Narrow Emission

AbstractWe present near-infrared spectra of young radio quasars selected by cross-correlating the Wide-field Infrared Survey Explorer (WISE) all-sky survey catalog with the radio catalog [Faint Images of the Radio Sky at Twenty cm (FIRST) and NRAO VLA Sky Survey (NVSS)]. The objects have typical redshifts of z ≈ 2 and [O III] luminosities of 107 erg s−1 comparable to those of luminous quasars. The observed flux ratios of narrow emission lines indicate that these objects appear to be powered by active galactic nuclei. The [O III] line is broad, with full width at half maximum ~1300 to 2100 km s−1, significantly larger than that of ordinary quasars. These large line widths might be explained by jet-induced outflows.

scholarly journals Studies of narrow emission lines in AGNs

1986 ◽  
Vol 119 ◽  
pp. 289-294
Author(s):  
Alexei V. Filippenko
Keyword(s):  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Emission Lines ◽  
As Species ◽  
Line Region ◽  
Narrow Line Region ◽  
High Velocity Clouds ◽  
Tight Correlation ◽  
Collisional Deexcitation ◽  
Narrow Emission

Optical spectra having moderately high resolution (~ 2 — 5 Å) are being used to study the profiles of narrow emission lines in active galactic nuclei (AGNs). It is often found that forbidden lines associated with high critical densities for collisional deexcitation are the broadest. A good example is [O III] λ4363 [ne(crit) ≈ 3 × 107 cm−3], whose width can be more than twice that of [O III] λ5007 [ne(crit) ≈ 8 × 105 cm−3]. The tight correlation between line width and ne(crit) implies that a much larger range of densities (∼ 102 — 107 cm−3) must be present among clouds in the narrow-line region than was previously believed. At times there almost appears to be a continuity between the narrow- and broad-line regions. In some objects the dense, high-velocity clouds are optically thick to ionizing radiation, since they emit [O I] λ6300 as well as species of much higher ionization (such as [Ne V] λ3426). These results help eliminate several difficulties in photoionization models of LINERs. It may also be possible to use the observed line widths as probes of the gravitational potential in AGNs.

scholarly journals Luminosity-dependent unification of active galactic nuclei and the X-ray Baldwin effect

2013 ◽  
Vol 553 ◽  
pp. A29 ◽  
Author(s):  
C. Ricci ◽  
S. Paltani ◽  
H. Awaki ◽  
P.-O. Petrucci ◽  
Y. Ueda ◽  
...  
Keyword(s):  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Baldwin Effect ◽  
X Ray

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.

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