Results 31 to 40 of about 132,127 (279)

Energy Flux and Particle Flux in Steady-state Solutions of Nuclear Star Clusters

The Astrophysical Journal, 2023
We examine the effects of two-body interactions in a nuclear star cluster surrounding a supermassive black hole. We evaluate the energy flux, analogously to the particle flux calculation of Bahcall and Wolf.
Barak Rom, Itai Linial, Re’em Sari
doaj   +1 more source

A tool to understand emission mechanisms of blazars through their high‐energy gamma‐ray emission

Astronomische Nachrichten, Volume 344, Issue 6, August 2023., 2023
The blazar SED is characterized by two energy components. Evidence suggests that the low‐energy component is generated by the synchrotron mechanism, but for the high‐energy component, the mechanism is still uncertain. Two main models have been proposed to explain this emission. According to the leptonic model, a correlation between the emission of both
Mabel Osorio, Erick Rangel, José Rodrigo Sacahui, María Magdalena González   +3 more
wiley   +1 more source

Unraveling the enigmatic soft x‐ray excess: Current understanding and future perspectives

Astronomische Nachrichten, Volume 344, Issue 6, August 2023., 2023
Abstract This article explores various theoretical models proposed to explain the soft x‐ray excess phenomenon, including warm Comptonization, ionized reflection models, and ionized outflowing disc winds. The soft x‐ray excess is better understood thanks to crucial observations made by ROSAT, XMM‐Newton, and eROSITA.
Thomas Boller
wiley   +1 more source

Multiwavelength astrophysics of the blazar OJ 287 and the project MOMO

Astronomische Nachrichten, Volume 344, Issue 4, May 2023., 2023
Abstract We are carrying out the densest and longest multiyear, multiwavelength monitoring project of OJ 287 ever done. The project MOMO (Multiwavelength Observations and Modeling of OJ 287) covers wavelengths from the radio to the high‐energy regime. A few selected observations are simultaneous with those of the Event Horizon Telescope (EHT).
S. Komossa, A. Kraus, D. Grupe, M.L. Parker, A. Gonzalez, L.C. Gallo, M.A. Gurwell, S. Laine, S. Yao, S. Chandra, L. Dey, J.L. Gómez, K. Hada, D. Haggard, A.R. Hollett, H. Jermak, S. Jorstad, T.P. Krichbaum, S. Markoff, C. McCall, J. Neilsen, M. Nowak   +21 more
wiley   +1 more source

Relativistic redshift of the star S0-2 orbiting the Galactic Center supermassive black hole [PDF]

Science, 2019
Gravitational redshift in the Galactic Center General relativity predicts that light emitted by an object in a strong gravitational field—for example, close to a black hole—should be shifted to longer wavelengths.
T. Do, A. Hees, A. Ghez, G. Martinez, D. Chu, S. Jia, S. Sakai, Jessica R. Lu, A. Gautam, K. K. O’neil, E. Becklin, M. Morris, K. Matthews, S. Nishiyama, R. Campbell, S. Chappell, Zhuo Chen, A. Ciurlo, A. Dehghanfar, E. Gallego-Cano, W. E. Kerzendorf, J. Lyke, S. Naoz, H. Saida, R. Schödel, M. Takahashi, Yohsuke Takamori, G. Witzel, P. Wizinowich   +28 more
semanticscholar   +1 more source

Visible Shapes of Black Holes M87* and SgrA*

Universe, 2020
We review the physical origins for possible visible images of the supermassive black hole M87* in the galaxy M87 and SgrA* in the Milky Way Galaxy. The classical dark black hole shadow of the maximal size is visible in the case of luminous background ...
Vyacheslav I. Dokuchaev, Natalia O. Nazarova   +1 more
doaj   +1 more source

Searching for overlooked TDEs in the 4XMM catalogue

Astronomische Nachrichten, Volume 344, Issue 4, May 2023., 2023
Abstract Tidal disruption events (TDEs) are usually discovered as bright transients, either in the X‐ray or optical/UV band. These events are often characterized by a “super‐soft” emission in the X‐ray band, which has not been observed in any other extragalactic source, with few exceptions (novae and supersoft active galactic nuclei, AGN), which can ...
Andrea Sacchi, Guido Risaliti, Giovanni Miniutti   +2 more
wiley   +1 more source

THE SINFONI BLACK HOLE SURVEY: THE BLACK HOLE FUNDAMENTAL PLANE REVISITED AND THE PATHS OF (CO)EVOLUTION OF SUPERMASSIVE BLACK HOLES AND BULGES [PDF]

, 2016
We investigate the correlations between the black hole (BH) mass MBH, the velocity dispersion σ, the bulge mass MBu, the bulge average spherical density &rgr; h ?> , and its spherical half-mass radius rh, constructing a database of 97 galaxies (31 core ...
R. Saglia, M. Opitsch, P. Erwin, Jens Thomas, A. Beifiori, M. Fabricius, X. Mazzalay, N. Nowak, S. Rusli, R. Bender   +9 more
semanticscholar   +1 more source

Measuring Distance and Properties of the Milky Way’s Central Supermassive Black Hole with Stellar Orbits [PDF]

, 2008
We report new precision measurements of the properties of our Galaxy’s supermassive black hole. Based on astrometric (1995-2007) and radial velocity (RV; 2000-2007) measurements from the W. M.
A. Ghez, S. Salim, N. Weinberg, N. Weinberg, Jessica R. Lu, T. Do, J. Dunn, K. Matthews, M. Morris, S. Yelda, E. Becklin, T. Kremenek, M. Milosavljevic, J. Naiman, J. Naiman   +14 more
semanticscholar   +1 more source

Winds in ultraluminous X‐ray sources: New challenges

Astronomische Nachrichten, Volume 344, Issue 4, May 2023., 2023
Abstract Ultraluminous X‐ray sources (ULXs) are extreme X‐ray binaries shining above 1039 erg/s, in most cases as a consequence of super‐Eddington accretion onto neutron stars and stellar‐mass black holes accreting above their Eddington limit. This was understood after the discovery of coherent pulsations, cyclotron lines, and powerful winds.
C. Pinto, P. Kosec
wiley   +1 more source