Results 31 to 40 of about 163,876 (250)

Local supermassive black holes, relics of active galactic nuclei and the X-ray background [PDF]

, 2003
We quantify the importance of mass accretion during AGN phases in the growth of supermassive black holes (BH) by comparing the mass function of black holes in the local universe with that expected from AGN relics, which are black holes grown entirely ...
A. Marconi, G. Risaliti, R. Gilli, L. Hunt, R. Maiolino, M. Salvati   +5 more
semanticscholar   +1 more source

Observational Evidence for Cosmological Coupling of Black Holes and its Implications for an Astrophysical Source of Dark Energy [PDF]

Astrophysical Journal Letters, 2023
Observations have found black holes spanning 10 orders of magnitude in mass across most of cosmic history. The Kerr black hole solution is, however, provisional as its behavior at infinity is incompatible with an expanding universe.
D. Farrah, K. Croker, M. Zevin, G. Tarlé, V. Faraoni, S. Petty, J. Afonso, N. Fernandez, K. Nishimura, C. Pearson, Lingyu Wang, D. Clements, A. Efstathiou, E. Hatziminaoglou, M. Lacy, C. McPartland, L. K. Pitchford, N. Sakai, Joel Weiner   +18 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, 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

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

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

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, Micic, Miroslav, Sigurdsson, Steinn   +2 more
core   +5 more sources

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

Probing the Mass Relation between Supermassive Black Holes and Dark Matter Halos at High Redshifts by Gravitational Wave Experiments

The Astrophysical Journal, 2023
Numerous observations have shown that almost all galaxies in our Universe host supermassive black holes (SMBHs), but there is still much debate about their formation and evolutionary processes. Recently, gravitational waves (GWs) have been expected to be
Kazuya Furusawa, Hiroyuki Tashiro, Shuichiro Yokoyama, Kiyotomo Ichiki   +3 more
doaj   +1 more source

The Coevolution of Galaxies and Supermassive Black Holes: Insights from Surveys of the Contemporary Universe [PDF]

, 2014
We summarize what large surveys of the contemporary Universe have taught us about the physics and phenomenology of the processes that link the formation and evolution of galaxies with their central supermassive black holes.
T. Heckman, P. Best
semanticscholar   +1 more source