Results 141 to 150 of about 50,755 (263)

Strong Amplitude Modulation of Hard-band X-Ray Quasiperiodic Oscillation with Soft-band Flux in RE J1034+396

The Astrophysical Journal
The X-ray quasiperiodic oscillation (QPO) is a remarkable form of variability in systems of compact object accretion. RE J1034+396, harboring the most significant X-ray QPO in active galactic nuclei (AGNs), is the most noteworthy source for in-depth ...
Ruisong Xia, Hao Liu, Yongquan Xue
doaj   +1 more source

Active galaxies and the diffuse Gamma-Ray background [PDF]

A model for the origin of relativistic particles and gamma rays in active galactic nuclei and quasars, together with recent HEAO-1 observations of the spectra of active galaxies from 2 to 165 keV, provide the basis for a reexamination of the nature of ...
Kazanas, D., Protheroe, R. J.
core   +1 more source

Scaling of Black Hole Accretion Discs from Gamma-Ray Bursts and Black Hole X-Ray Binaries to Active Galactic Nuclei [PDF]

, 2006
J. I. Katz
openalex   +1 more source

X-ray absorption in Active Galactic Nuclei

, 2015
I Nuclei Galattici Attivi (AGN) sono tra le sorgenti più luminose dell’Universo e sono osservati in circa 10-20% delle galassie nell’Universo locale. Il meccanismo di generazione dell’energia di queste sorgenti è l’accrescimento di materia su un buco nero supermassivo (SMBH). Secondo il paradigma del Modello Unificato (UM) il SMBH è circondato da un
openaire   +1 more source

Obscured and unobscured X-ray active galactic nuclei

Astronomy & Astrophysics
Context. Active galactic nuclei (AGNs) play a crucial role in galaxy evolution by influencing the observational properties of their host galaxies. Aims. We aim to investigate the host-galaxy properties of X-ray selected AGNs, focusing on differences between obscured and unobscured AGNs, and between high-excitation sources (log([O III]λ5007/Hβ ≥ 0.5 ...
C. G. Bornancini, G. A. Oio, G. Coldwell
openaire   +1 more source

PEARLS: NuSTAR and XMM-Newton Extragalactic Survey of the JWST North Ecliptic Pole Time-domain Field II

The Astrophysical Journal
We present the second NuSTAR and XMM-Newton extragalactic survey of the JWST north ecliptic pole (NEP) time-domain field (TDF). The first NuSTAR NEP-TDF survey had 681 ks total exposure time executed in NuSTAR cycle 5 in 2019 and 2020. This second survey,
Xiurui Zhao, Francesca Civano, Christopher N. A. Willmer, Silvia Bonoli, Chien-Ting Chen, Samantha Creech, Renato Dupke, Francesca M. Fornasini, Rolf A. Jansen, Satoshi Kikuta, Anton M. Koekemoer, Sibasish Laha, Stefano Marchesi, Rosalia O’Brien, Ross Silver, S. P. Willner, Rogier A. Windhorst, Haojing Yan, Jailson Alcaniz, Narciso Benitez, Saulo Carneiro, Javier Cenarro, David Cristóbal-Hornillos, Alessandro Ederoclite, Antonio Hernán-Caballero, Carlos López-Sanjuan, Antonio Marín-Franch, Claudia Mendes de Oliveira, Mariano Moles, Laerte Sodré Jr., Keith Taylor, Jesús Varela, Héctor Vázquez Ramió   +32 more
doaj   +1 more source

Very High Redshift X-Ray–selected Active Galactic Nuclei in the Chandra Deep Field–North [PDF]

, 2003
A. J. Barger, L. L. Cowie, P. Capak, D. M. Alexander, F. E. Bauer, W. N. Brandt, G. P. Garmire, A. E. Hornschemeier   +7 more
openalex   +1 more source

Chandra X-Ray Observatory Study of the X-Ray Emission of PKS 0023−26 and Comparison with Recent ALMA Results

The Astrophysical Journal
We present a deep high-resolution Chandra X-ray Observatory study of the powerful compact radio source PKS 0023−26 associated with a quasar at redshift 0.322.
A. Siemiginowska, R. Morganti, G. Fabbiano, E. O’Sullivan, T. Oosterloo, C. Tadhunter, D. Burke   +6 more
doaj   +1 more source

Cosmic ray feedback in galaxies and galaxy clusters: A pedagogical introduction and a topical review of the acceleration, transport, observables, and dynamical impact of cosmic rays. [PDF]

Astron Astrophys Rev, 2023
Ruszkowski M, Pfrommer C.
europepmc   +1 more source

X-ray spectral parameters for a sample of 95 active galactic nuclei [PDF]

, 2015
A. A. Vasylenko, V. I. Zhdanov, E. V. Fedorova   +2 more
openalex   +1 more source