scholarly journals The irradiated ISM of ULIRGs

2007 ◽  
Vol 3 (S242) ◽  
pp. 452-456
Author(s):  
M. Spaans ◽  
R. Meijerink ◽  
F. P. Israel ◽  
A. F. Loenen ◽  
W. A. Baan
Keyword(s):  
Black Hole ◽  
Ultraviolet Radiation ◽  
Young Stars ◽  
Molecular Gas ◽  
X Rays ◽  
Central Black Hole ◽  
Far Ultraviolet ◽  
Very High

AbstractThe nuclei of ULIRGs harbor massive young stars, an accreting central black hole, or both. Results are presented for molecular gas that is exposed to X-rays (1–100 keV, XDRs) and far-ultraviolet radiation (6–13.6 eV, PDRs). Attention is paid to species like HCO+, HCN, HNC, OH, H2O and CO. Line ratios of HCN/HCO+ and HNC/HCN discriminate between PDRs and XDRs. Very high J (>10) CO lines, observable with HIFI/Herschel, discriminate very well between XDRs and PDRs. In XDRs, it is easy to produce large abundances of warm (T > 100 k) H2O and OH. In PDRs, only OH is produced similarly well.

scholarly journals Quasars Disks and Cosmology

1987 ◽  
Vol 124 ◽  
pp. 695-696
Author(s):  
Hagai Netzer
Keyword(s):  
Black Hole ◽  
Ultraviolet Radiation ◽  
Equivalent Width ◽  
Selection Effect ◽  
Emission Lines ◽  
Line Of Sight ◽  
Apparent Brightness ◽  
Central Black Hole ◽  
New Ideas ◽  
Thin Disks

Much of the optical and ultraviolet radiation of bright quasars may originate in a massive accretion disk around a central black hole. Most searches for the signature of such disks gave ambiguous results but lately there are new ideas that may lead to their discovery. In particular, the apparent brightness of thin disks depend on their inclination to the observer's line of sight and this may be detected by the equivalent width of some emission lines (Netzer 1985, 1986). This idea may change our view on the inner structure of quasars and other AGN. In addition, it points to a potential selection effect that has not been taken into account so far. Magnitude limited optical quasar samples may contain, preferentially, face-on disks, thus cosmological evolution based on such samples may be biased. There are other implications, especially to the observed correlation of Lop with Lx in quasars.

scholarly journals X-rays from Photoionized Accretion Discs

1994 ◽  
Vol 159 ◽  
pp. 380-380
Author(s):  
G. Matt ◽  
A.C. Fabian ◽  
R.R. Ross
Keyword(s):  
Black Hole ◽  
Seyfert Galaxies ◽  
High Energy ◽  
Accretion Disc ◽  
Accretion Discs ◽  
X Rays ◽  
Central Black Hole ◽  
X Ray

The presence of iron lines and high energy excesses in the X-ray spectra of Seyfert galaxies has been firmly established by Ginga (e.g. Nandra & Pounds 1993 and references therein). These features are generally interpreted as signatures of the reprocessing of the primary X-rays by matter in the neighbourhood of the central black hole, probably distributed in an accretion disc (Lightman & White 1988, George & Fabian 1991, Matt, Perola & Piro 1991).

scholarly journals PROBING THE CENTRAL BLACK HOLE IN M87 WITH GAMMA-RAYS

2012 ◽  
Vol 27 (28) ◽  
pp. 1230030 ◽  
Author(s):  
FRANK M. RIEGER ◽  
FELIX AHARONIAN
Keyword(s):  
Black Hole ◽  
Large Scale ◽  
Gamma Ray ◽  
High Sensitivity ◽  
High Energy ◽  
X Rays ◽  
Central Black Hole ◽  
Central Engine ◽  
Very High Energy ◽  
Observational Status

Recent high-sensitivity observation of the nearby radio galaxy M87 has provided important insights into the central engine that drives the large-scale outflows seen in radio, optical and X-rays. This review summarizes the observational status achieved in the high energy (HE < 100 GeV) and very high energy (VHE > 100 GeV) gamma-ray domains, and discusses the theoretical progress in understanding the physical origin of this emission and its relation to the activity of the central black hole.

Feeding and feedback in the nucleus of NGC 613

2019 ◽  
Vol 15 (S359) ◽  
pp. 364-365
Author(s):  
Patrícia da Silva ◽  
J. E. Steiner ◽  
R. B. Menezes
Keyword(s):  
Black Hole ◽  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Hii Regions ◽  
Stellar Populations ◽  
Host Galaxy ◽  
Molecular Gas ◽  
X Rays ◽  
Supermassive Black Hole ◽  
Feeding Process

AbstractActive Galactic Nuclei (AGN) are objects in which a supermassive black hole is fed by gas and, as this generates energy, can ionise the environment and interact with it by jets and winds. This work is focused on the processes of feeding and feedback in the nucleus of NGC 613. This object is a case in which both phenomena can be studied in some detail. The kinematics and morphology of the molecular gas trace the feeding process while the ionization cone, seen in [O iii]λ5007 and soft X-rays, as well as the radio jet and wind/outflows are associated with feedback processes. In addition, we see 10 HII regions, associated with nuclear and circumnuclear young stellar populations, dominant in the optical, that makes the analysis complicated, though more interesting. For all these phenomena, NGC 613 nucleus is a vibrant example of the interplay between the AGN and the host galaxy.

scholarly journals Multi-frequency, multi-epoch VLBI observations of the M87 jet

2013 ◽  
Vol 9 (S304) ◽  
pp. 106-107
Author(s):  
Kazuhiro Hada ◽  
Marcello Giroletti ◽  
Gabriele Giovannini ◽  
Akihiro Doi ◽  
Motoki Kino ◽  
...  
Keyword(s):  
Black Hole ◽  
Physical Properties ◽  
High Energy ◽  
Radio Flux ◽  
Central Black Hole ◽  
Vlbi Observations ◽  
Very High Energy ◽  
Nuclear Opacity ◽  
Γ Ray ◽  
Very High

AbstractWe present some of preliminary results obtained by our dense monitoring project of the M87 jet with VERA 22 and 43 GHz starting from October 2010. The aims of this monitor are to clarify the detailed physical properties of the M87 jet base near the black hole, including the connection to γ-ray productions, jet kinematics and nuclear opacity. We detected a remarkable increase of the radio flux from the jet base of M87 during an elevated very-high-energy γ-ray activity occurred in the early 2012, suggesting that the γ-ray is produced in the immediate vicinity of the central black hole.

scholarly journals The MBHBM⋆ Project. I. Measurement of the Central Black Hole Mass in Spiral Galaxy NGC 3504 Using Molecular Gas Kinematics

2020 ◽  
Vol 892 (1) ◽  
pp. 68 ◽  
Author(s):  
Dieu D. Nguyen ◽  
Mark den Brok ◽  
Anil C. Seth ◽  
Timothy A. Davis ◽  
Jenny E. Greene ◽  
...  
Keyword(s):  
Black Hole ◽  
Spiral Galaxy ◽  
Molecular Gas ◽  
Black Hole Mass ◽  
Central Black Hole ◽  
Gas Kinematics

Another canonical time variation of X-rays from black hole candidates in the very high flare state?

1993 ◽  
Vol 403 ◽  
pp. L39 ◽  
Author(s):  
Sigenori Miyamoto ◽  
Sayuri Iga ◽  
Shunji Kitamoto ◽  
Yasuhide Kamado
Keyword(s):  
Black Hole ◽  
Time Variation ◽  
X Rays ◽  
Very High ◽  
Black Hole Candidates

scholarly journals Low-Activity Nuclei in Spiral Galaxies

1989 ◽  
Vol 134 ◽  
pp. 517-517
Author(s):  
G. Fabbiano
Keyword(s):  
Black Hole ◽  
Spiral Galaxies ◽  
Soft Component ◽  
X Rays ◽  
Central Black Hole ◽  
X Ray ◽  
Optical Line ◽  
Einstein Observatory ◽  
Low Activity ◽  
Normal Spiral

Two types of active nuclei have been observed in normal spiral galaxies in X-rays with the Einstein Observatory: low-activity AGN, and starburst regions. The prototype of the first kind is the nucleus of M81 (Elvis and Van Speybroeck 1982; Fabbiano 1988a), but similar nuclei might also be those of M33 and NGC 1313. Soft X-ray spectra of these nuclei suggest relatively steep soft X-ray components (Trinchieri, Fabbiano and Peres 1988; Fabbiano and Trinchieri 1987; Fabbiano 1988a), reminiscent of those observed in QSOs by Bechtold et al (1987) and Wilkes and Elvis (1987). In M81, in particular, this soft component might supply enough photons to explain the optical line spectrum. If this soft X-ray component originates from an accretion disk surrounding a central black hole, the mass of the latter is likely to be smaller than 104–5 solar masses.

scholarly journals NONTHERMAL RADIATION FROM CYGNUS X-1 CORONA

2010 ◽  
Vol 19 (06) ◽  
pp. 783-789
Author(s):  
FLORENCIA L. VIEYRO ◽  
GUSTAVO E. ROMERO ◽  
GABRIELA S. VILA
Keyword(s):  
Black Hole ◽  
Electromagnetic Emission ◽  
Photon Absorption ◽  
X Rays ◽  
Nonthermal Radiation ◽  
Black Hole Candidate ◽  
Electron Positron ◽  
Hot Plasma ◽  
Hard State ◽  
Very High

Cygnus X-1 was the first X–ray source widely accepted to be a black hole candidate, and remains among the most studied astronomical objects in its class. The detection of nonthermal radio, hard X–rays and gamma-rays reveals the fact that this kind of objects are capable of accelerating particles up to very high energies. In order to explain the electromagnetic emission from Cygnus X-1 in the low-hard state we present a model of a black hole corona with both relativistic lepton and hadron content. We characterize the corona as a two-temperature hot plasma plus a mixed nonthermal population in which energetic particles interact with magnetic, photon and matter fields. Our calculations include the radiation emitted by secondary particles (pions, muons and electron–positron pairs). Finally, we take into account the effects of photon absorption. We compare the results obtained from our model with data of Cygnus X-1 obtained by the COMPTEL instrument.

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