scholarly journals Wolf-Rayet stars in Active Galactic Nuclei

1999 ◽  
Vol 193 ◽  
pp. 760-761
Author(s):  
Robin J.R. Williams ◽  
John E. Dyson ◽  
Judith J. Perry
Keyword(s):  
Black Hole ◽  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Active Galaxies ◽  
Emission Lines ◽  
Supply Rate ◽  
Stellar Cluster ◽  
Uv Emission ◽  
Ram Pressure

Starbursts, black holes and AGN have strong observational links, as discussed elsewhere in these proceedings. Perry & Dyson (1985 (PD), see also Perry 1994) studied the role of shocks around supernovae and stellar wind bubbles in the nuclei of active galaxies. Both the ejecta and the ambient ISM are initially shocked to high temperatures. PD found that while the shocked gas is maintained at high pressure by ram pressure, it cools rapidly, to then produce the observed optical and UV emission lines. The mass supply rate from the nuclear starburst, inferred from the strength of the emission lines, tallies well with that required by an accreting black hole to generate the observed luminosity. A symbiosis between a starburst stellar cluster and an accreting black hole naturally generates the observational features associated with QSOs.

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.

Supermassive Black Holes in Active Galactic Nuclei. I. The Consistency of Black Hole Masses in Quiescent and Active Galaxies

2001 ◽  
Vol 555 (2) ◽  
pp. L79-L82 ◽  
Author(s):  
Laura Ferrarese ◽  
Richard W. Pogge ◽  
Bradley M. Peterson ◽  
David Merritt ◽  
Amri Wandel ◽  
...  
Keyword(s):  
Black Holes ◽  
Black Hole ◽  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Supermassive Black Holes ◽  
Active Galaxies ◽  
Black Hole Masses

Searching for warped disk AGN candidates

2017 ◽  
Vol 13 (S336) ◽  
pp. 135-136
Author(s):  
E. Fedorova ◽  
B. I. Hnatyk ◽  
V. I. Zhdanov ◽  
A. Vasylenko
Keyword(s):  
Black Hole ◽  
Energy Range ◽  
Active Galactic Nuclei ◽  
Accretion Disks ◽  
Complex Shape ◽  
Galactic Nuclei ◽  
Emission Lines ◽  
Central Black Hole ◽  
Maser Emission ◽  
Additional Information

AbstractMapping the maser emission of subnuclear regions of active galactic nuclei (AGN) enable us to determine some interesting details of the geometry of the accretion disks (AD) under the condition that they have “maser skin”. Additional information about disk warp in the innermost zone near the central black hole (BH) can be disclosed by means of modeling the shape of the relativistically broadened iron emission lines in the energy range 6-7 keV. Here we analyze the influence of the AD geometry (warp) on the shape of the set of relativistically broadened emission lines, as well as consider some examples of AGNs identified by maser mapping techinque as warped and having the complex shape of iron lines near 6.4 keV.

Radio galaxies with and without emission lines

2020 ◽  
Vol 15 (S359) ◽  
pp. 396-401
Author(s):  
Grażyna Stasińska ◽  
Natalia Vale Asari ◽  
Dorota Kozieł-Wierzbowska
Keyword(s):  
Black Hole ◽  
Active Galactic Nuclei ◽  
Equivalent Width ◽  
Galactic Nuclei ◽  
Optical Emission ◽  
Radio Galaxies ◽  
Emission Lines ◽  
The Common ◽  
Black Hole Masses

AbstractUsing the recent ROGUE I catalogue of galaxies with radio cores (Kozie_l-Wierzbowska et al. 2020) and after selecting the objects which are truly radio active galactic nuclei, AGNs, (which more than doubles the samples available so far), we perform a thorough comparison of the properties of radio galaxies with and without optical emission lines (galaxies where the equivalent width of Hα is smaller than 3Å are placed in the last category). We do not find any strong dichotomy between the two classes as regards the radio luminosities or black hole masses. The same is true when using the common classification into high- and low-excitation radio galaxies (HERGs and LERGs respectively).

scholarly journals Mechanical heating by active galaxies

2005 ◽  
Vol 363 (1828) ◽  
pp. 655-665 ◽  
Author(s):  
Mitchell C. Begelman ◽  
Mateusz Ruszkowski
Keyword(s):  
Active Galactic Nuclei ◽  
Excess Entropy ◽  
Galactic Nuclei ◽  
Active Galaxies ◽  
Clusters Of Galaxies ◽  
Heating Mechanism ◽  
Central Regions ◽  
Radiative Losses ◽  
Analytic Models

Jets and winds are significant channels for energy loss from accreting black holes. These outflows mechanically heat their surroundings, through shocks as well as gentler forms of heating. We discuss recent efforts to understand the nature and distribution of mechanical heating by central active galactic nuclei (AGN) in clusters of galaxies, using numerical simulations and analytic models. Specifically, we will discuss whether the relatively gentle ‘effervescent heating’ mechanism can compensate for radiative losses in the central regions of clusters, and account for the excess entropy observed at larger radii. J. Binney (2005 Phil. Trans. R. Soc. A , 363 , 739−749, doi: 10.1098/rsta.2004.1520) discusses the possible role of violent, episodic heating by AGN in clusters.

scholarly journals Broad UV Emission Lines in Type-1 Active Galactic Nuclei: A Note on Spectral Diagnostics and the Excitation Mechanism

Atoms ◽  
2020 ◽  
Vol 8 (4) ◽  
pp. 94
Author(s):  
Paola Marziani ◽  
Ascension del Olmo ◽  
Jaime Perea ◽  
Mauro D’Onofrio ◽  
Swayamtrupta Panda
Keyword(s):  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
General Purpose ◽  
Emission Lines ◽  
Impact Excitation ◽  
Ionization Degree ◽  
Uv Emission ◽  
Spectral Diagnostics ◽  
Ionization Parameter

This paper reviews several basic emission properties of the UV emission lines observed in the spectra of quasars and type-1 active galactic nuclei, mainly as a function of the ionization parameter, metallicity, and density of the emitting gas. The analysis exploits a general-purpose 4D array of the photoionization simulations computed using the code CLOUDY, covering ionization parameter in the range 10−4.5–10+1.0, hydrogen density nH∼107–1014 cm−3, metallicity Z between 0.01 and 100 Z⊙, and column density in the range 1021–1023 cm−2. The focus is on the most prominent UV emission lines observed in quasar spectra, namely Nvλ1240, Siivλ1397, Oiv]λ1402, Civλ1549, Heiiλ1640, Aliiiλ1860, Siiii]λ1892, and Ciii]λ1909, and on the physical conditions under which electron-ion impact excitation is predicted to be the dominant line producer. Photoionization simulations help constrain the physical interpretation and the domain of applicability of spectral diagnostics derived from measurements of emission line ratios, reputed to be important for estimating the ionization degree, density, and metallicity of the broad line emitting gas, as well as the relative intensity ratios of the doublet or multiplet components relevant for empirical spectral modeling.

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