scholarly journals 5.13. High-density-and-temperature circumnuclear molecular torus in M51

1998 ◽  
Vol 184 ◽  
pp. 237-238
Author(s):  
S. Matsushita ◽  
K. Kohno ◽  
B. Vila-Vilaro ◽  
R. Kawabe ◽  
T. Tosaki
Keyword(s):  
Active Galactic Nuclei ◽  
Molecular Clouds ◽  
Galactic Nuclei ◽  
Active Galaxies ◽  
High Density ◽  
Molecular Gas ◽  
Physical Conditions

It is very important to know the physical conditions of circumnuclear molecular gas in order to understand the nature of Active Galactic Nuclei (AGN), since the circumnuclear molecular gas in active galaxies might be directly affected by or is affecting the activity of nucleus. To investigate the physical conditions of the molecular clouds in detail, multi-line observations with millimeter arrays are essential.

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.

scholarly journals Intrinsic physical conditions and structure of relativistic jets in active galactic nuclei

2015 ◽  
Vol 447 (3) ◽  
pp. 2726-2737 ◽  
Author(s):  
E. E. Nokhrina ◽  
V. S. Beskin ◽  
Y. Y. Kovalev ◽  
A. A. Zheltoukhov
Keyword(s):  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Relativistic Jets ◽  
Physical Conditions

scholarly journals Gas Dynamics and Active Phenomena in Galactic Nuclei: M100 and M94

1996 ◽  
Vol 157 ◽  
pp. 247-249
Author(s):  
Kazushi Sakamoto ◽  
Takeo Minezaki ◽  
Keiichi Wada ◽  
Sachiko Okumura ◽  
Yukiyasu Kobayashi
Keyword(s):  
Gravitational Potential ◽  
Gas Dynamics ◽  
Molecular Clouds ◽  
Galactic Nuclei ◽  
Trace Gas ◽  
Molecular Gas ◽  
Barred Galaxies ◽  
Nir Imaging ◽  
Oval Distortion

Since molecular gas fuels AGNs and molecular clouds form stars, understanding of molecular gas dynamics is a key to the understanding of active phenomena (such as starbursts and AGNs) in galactic nuclei. To study gas dynamics in weakly barred galaxies, we made CO interferometry (to trace gas) and NIR imaging (to trace stars) toward two nearby SAB galaxies M100 and M94. Each galaxy has a small stellar nuclear bar and also has an outer bar or oval distortion, thus suitable for the study of gas dynamics in a barred gravitational potential. Observations were made using Nobeyama Millimeter Array (NMA) and the IRcamera PICNIC installed at the ISAS 1.3 m telescope.

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 A Helical Magnetic Field Model of the Jets

1987 ◽  
Vol 115 ◽  
pp. 381-383
Author(s):  
T. Maruyama ◽  
M. Fujimoto
Keyword(s):  
Magnetic Field ◽  
Active Galactic Nuclei ◽  
Lorentz Force ◽  
Field Model ◽  
Galactic Nuclei ◽  
Molecular Gas ◽  
Magnetic Field Model ◽  
Helical Magnetic Field ◽  
Jet Axis

A hydromagnetic model is presented for the bipolar flow of molecular gas from newborn stars and for the radio jet emerging out of active galactic nuclei. We assume a tightly-twisted helical magnetic field in the jet, which can collimate and accelerate the gas along the jet axis. The Lorentz force is also shown to rotate the gas around it.

scholarly journals Quasar Evolution and the Growth of Black Holes in the Nuclei of Active Galaxies

1989 ◽  
Vol 134 ◽  
pp. 233-239
Author(s):  
R. D. Blandford
Keyword(s):  
Black Holes ◽  
Active Galactic Nuclei ◽  
Radiation Pressure ◽  
High Redshift ◽  
Galactic Nuclei ◽  
Rapid Decrease ◽  
Active Galaxies ◽  
Host Galaxy ◽  
Nearby Galaxies ◽  
The Mean

The observed evolutionary behavior of active galactic nuclei is compatible with a model in which black holes form in the nuclei of new-born galaxies and then grow at a rate limited by both radiation pressure and the supply of gas. Individual sources become more luminous with time as long as they are being fueled. However, the rapid decrease in the mean rate of supply of gas causes a strong decline in the space density of active objects. Nearby galaxies should harbor modest size (∼ 106 – 108 M⊙) black holes. It is suggested that the gas that fuels high redshift quasars is mostly derived from the host galaxy.

scholarly journals THE CENTRAL MOLECULAR GAS STRUCTURE IN LINERS WITH LOW-LUMINOSITY ACTIVE GALACTIC NUCLEI: EVIDENCE FOR GRADUAL DISAPPEARANCE OF THE TORUS

2012 ◽  
Vol 763 (1) ◽  
pp. L1 ◽  
Author(s):  
F. Müller-Sánchez ◽  
M. A. Prieto ◽  
M. Mezcua ◽  
R. I. Davies ◽  
M. A. Malkan ◽  
...  
Keyword(s):  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Molecular Gas ◽  
Gradual Disappearance
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