Results 131 to 140 of about 50,261 (220)

Revealing an Oscillating and Contracting Compact Corona near the Event Horizon of the Supermassive Black Hole in 1ES 1927+654

The Astrophysical Journal Letters
Dynamic processes in the accretion flow near black holes produce X-ray flux variability, sometimes quasiperiodic. Determining its physical origin is key to mapping the accretion geometry but remains unresolved.
Qing-Cang Shui, Shu Zhang, Shuang-Nan Zhang, Hua Feng, Yu-Peng Chen, Long Ji, Ling-Da Kong, Liang Zhang, Jing-Qiang Peng, Peng-Ju Wang   +9 more
doaj   +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

Signature of a Seyfert-like Component in Blazar 3C 273 and Its Reflection-based Explanation

The Astrophysical Journal
We present the results of blazar 3C 273 from simultaneous observations obtained using the XMM-Newton and NuSTAR satellites during the period 2015–2019 in five epochs. When the spectra are modeled with a power law, significant residuals arise below ∼2 keV
Haritma Gaur, Main Pal, Muhammad S. Anjum, Kiran Wani, Pankaj Kushwaha, Ashwani Pandey, Liang Chen   +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

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

X-ray spectra and time variability of active galactic nuclei [PDF]

The X-ray spectra of broad line active galactic nuclei (AGN) of all types (Seyfert I's, NELG's, broadline radio galaxies) are well fit by a power law in the .5 to 100 keV band of man energy slope alpha = .68 + or - .15.
Mushotzky, R. F.
core   +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

BASS. XLVIII. [Ne V] λ3427 Emission in Powerful Nearby Active Galactic Nuclei

The Astrophysical Journal
We investigate the high-ionization, narrow [Ne V ] λ 3427 line emission in a sample of over 340 ultrahard X-ray (14–195 keV) selected active galactic nuclei (AGN) drawn from the BAT AGN Spectroscopic Survey project.
Tomer Reiss, Benny Trakhtenbrot, Claudio Ricci, Franz E. Bauer, Michael J. Koss, Kohei Ichikawa, Darshan Kakkad, Richard Mushotzky, Kyuseok Oh, Alessandro Peca, Rudolf Bär, Yaherlyn Diaz, Fiona Harrison, Meredith C. Powell, Eleonora Sani, Daniel Stern, C. Megan Urry   +16 more
doaj   +1 more source

Optical characteristics of young quasars as sources of the cosmic X-ray background [PDF]

The sources which dominate the thermal cosmic X-ray background cannot have X-ray spectra similar to the power laws measured for bright active galactic nuclei.
Boldt, E., Leiter, D.
core   +1 more source

X-Ray Constraints on Wandering Black Holes in Stripped Galaxy Nuclei in the Halo of NGC 5128

The Astrophysical Journal
A subset of galaxies have dense nuclei, and when these galaxies are accreted and tidally stripped, the nuclei can masquerade as globular clusters in the halos of large galaxies.
Samuel L. Feyan, Ryan Urquhart, Jay Strader, Anil C. Seth, David J. Sand, Nelson Caldwell, Denija Crnojević, Antoine Dumont, Karina Voggel   +8 more
doaj   +1 more source