Results 21 to 30 of about 32,039 (196)
Modeling the Central Supermassive Black Hole Mass of Quasars via the LSTM Approach
The Astrophysical Journal, 2023 One of the fundamental questions about quasars is related to their central supermassive black holes. The reason for the existence of these black holes with such a huge mass is still unclear, and various models have been proposed to explain them. However,
Seyed Sajad Tabasi +3 more
doaj +1 more source
Physics World, 2002 After a brief historical introduction, we summarize current efforts and accomplishments in the study of supermassive black holes.
Ferrarese, Laura, Merritt, David
openaire +2 more sources
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 +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
Supermassive Black Holes [PDF]
Journal of High Energy Physics, Gravitation and Cosmology, 2019 In the following black hole model, electrons and positrons form a neutral gas which is confined by gravitation. The smaller masses are supported against gravity by electron degeneracy pressure. Larger masses are supported by ideal gas and radiation pressure. In each case, the gas is a polytrope which satisfies the Lane-Emden equation.
openaire +2 more sources
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 +21 more
wiley +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 +2 more
wiley +1 more source
The Role of Primordial Kicks on Black Hole Merger Rates [PDF]
, 2005 Primordial stars are likely to be very massive $\geq30\Msun$, form in isolation, and will likely leave black holes as remnants in the centers of their host dark matter halos in the mass range $10^{6}-10^{10}\Ms$. Such early black holes, at redshifts z$\
Abel, Tom +2 more
core +5 more sources
Supermassive black hole ancestors [PDF]
Monthly Notices of the Royal Astronomical Society, 2012 12 pages, 9 figures, 1 table, MNRAS in ...
Petri, Andrea +2 more
openaire +3 more sources
Shadow of rotating and twisting charged black holes with cloud of strings and quintessence
European Physical Journal C: Particles and Fields, 2023 Testing gravity theories is an important and interesting issue in relativistic astrophysics using astrophysical observations. In recent years, Event horizon telescope collaboration provided valuable data from shadow of supermassive black holes located at
Muhammad Zahid +4 more
doaj +1 more source