Results 31 to 40 of about 166,156 (289)
Looking for ultralight dark matter near supermassive black holes [PDF]
Journal of Cosmology and Astroparticle Physics, 2019 Measurements of the dynamical environment of supermassive black holes (SMBHs) are becoming abundant and precise. We use such measurements to look for ultralight dark matter (ULDM), which is predicted to form dense cores (“solitons”) in the centre of ...
Nitsan Bar +3 more
semanticscholar +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
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
Supermassive black holes and their feedback effects in the IllustrisTNG simulation [PDF]
Monthly notices of the Royal Astronomical Society, 2017 We study the population of supermassive black holes (SMBHs) and their effects on massive central galaxies in the IllustrisTNG cosmological hydrodynamical simulations of galaxy formation.
R. Weinberger +10 more
semanticscholar +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 +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
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
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
Fourier spectral‐timing techniques for the study of accreting black holes
Astronomische Nachrichten, Volume 344, Issue 4, May 2023., 2023 Abstract The X‐ray signal from active galactic nuclei and black hole (BH) X‐ray binaries is highly variable on a range of timescales. This variability can be exploited to map the region of interest close to the BH, which is far too small to directly image for all but two BHs in the Universe.
Adam Ingram
wiley +1 more source