Results 41 to 50 of about 132,127 (279)
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
EHT Constraint on the Ultralight Scalar Hair of the M87 Supermassive Black Hole [PDF]
Universe, 2019 Hypothetical ultralight bosonic fields will spontaneously form macroscopic bosonic halos around Kerr black holes, via superradiance, transferring part of the mass and angular momentum of the black hole into the halo.
P. Cunha, C. Herdeiro, E. Radu
semanticscholar +1 more source
Universe, 2019 We propose the simple new method for extracting the value of the black hole spin from the direct high-resolution image of black hole by using a thin accretion disk model.
Vyacheslav I. Dokuchaev +1 more
doaj +1 more source
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
A Global Inventory of Feedback
Galaxies, 2023 Feedback from both supermassive black holes and massive stars plays a fundamental role in the evolution of galaxies and the inter-galactic medium. In this paper, we use available data to estimate the total amount of kinetic energy and momentum created ...
Timothy M. Heckman, Philip N. Best
doaj +1 more source
Extreme accretion events: TDEs and changing‐look AGN
Astronomische Nachrichten, Volume 344, Issue 4, May 2023., 2023 Abstract We present a review of the topics of X‐ray stellar tidal disruption events (TDEs) and changing‐look active galactic nuclei (AGN). Stars approaching a supermassive black hole (SMBH) can be tidally disrupted and accreted. TDEs were first discovered in the X‐ray regime and appear as luminous, giant‐amplitude flares from inactive galaxies.
S. Komossa, D. Grupe
wiley +1 more source
Shadow of a rotating squashed Kaluza-Klein black hole
Journal of High Energy Physics, 2019 We study the shadow of a rotating squashed Kaluza-Klein (KK) black hole and the shadow is found to possess distinct properties from those of usual rotating black holes.
Fen Long +3 more
doaj +1 more source
Astronomische Nachrichten, Volume 344, Issue 4, May 2023., 2023 Abstract The non‐linear correlation between the UV and X‐ray emission observed in active galactic nuclei remains a puzzling question that challenges accretion models. While the UV emission originates from the cold disk, the X‐ray emission is emitted by a hot corona whose physical characteristics and geometry are still highly debated.
S. Barnier +3 more
wiley +1 more source
Two-temperature, Magnetically Arrested Disc simulations of the jet from the supermassive black hole in M87 [PDF]
Monthly notices of the Royal Astronomical Society, 2018 We present two-temperature, radiative general relativistic magnetohydrodynamic simulations of Magnetically Arrested Discs (MAD) that launch powerful relativistic jets.
A. Chael, R. Narayan, Michael D. Johnson
semanticscholar +1 more source
No Supermassive Black Hole in M33?
Science, 2001 We observed the nucleus of M33, the third-brightest galaxy in the Local Group, with the Space Telescope Imaging Spectrograph at a resolution at least a factor of 10 higher than previously obtained. Rather than the steep rise expected within the radius of gravitational influence of a supermassive black hole, the random stellar velocities showed a ...
David Merritt +2 more
openaire +4 more sources