Results 91 to 100 of about 1,919 (235)

Stripe 82-XL: The ∼54.8 deg2 and ∼18.8 Ms Chandra and XMM-Newton Point-source Catalog and Number of Counts

The Astrophysical Journal
We present an enhanced version of the publicly available Stripe 82X catalog (S82-XL), featuring a comprehensive set of 22,737 unique X-ray point sources identified with a significance ≳4 σ .
Alessandro Peca, Nico Cappelluti, Stephanie LaMassa, C. Megan Urry, Massimo Moscetti, Stefano Marchesi, David Sanders, Connor Auge, Aritra Ghosh, Tonima Tasnim Ananna, Núria Torres-Albà, Ezequiel Treister   +11 more
doaj   +1 more source

First X-Ray Polarimetric View of a Low-luminosity Active Galactic Nucleus: The Case of NGC 2110

The Astrophysical Journal
Low-luminosity active galactic nuclei (LLAGN) provide a unique view of Comptonization and nonthermal emission from accreting black holes in the low accretion rate regime.
Sudip Chakraborty, Ajay Ratheesh, Daniele Tagliacozzo, Philip Kaaret, Jakub Podgorný, Frédéric Marin, Francesco Tombesi, Steven R. Ehlert, Chien-Ting J. Chen, Dawoon E. Kim, Ioannis Liodakis, Francesco Ursini, Riccardo Middei, Alessandro Di Marco, Fabio La Monaca, Srimanta Banerjee, Keigo Fukumura, W. Peter Maksym, Romana Mikušincová, Rodrigo Nemmen, Pierre-Olivier Petrucci, Paolo Soffitta, Jiří Svoboda, Wenda Zhang   +23 more
doaj   +1 more source

First Evidence for a Quasiperiodic Oscillation Triplet and Its Relativistic Precession Origin in RE J1034+396

The Astrophysical Journal
Quasiperiodic oscillations (QPOs) in active galactic nuclei (AGNs) provide a powerful tool for probing the structure of the innermost accretion flow and corona around supermassive black holes.
Ruisong Xia, Yongquan Xue, Jialai Wang, Hao Liu   +3 more
doaj   +1 more source

XRISM Spectroscopy of Accretion-driven Wind Feedback in NGC 4151

The Astrophysical Journal Letters
The hottest, most ionized, and fastest winds driven by accretion onto massive black holes have the potential to reshape their host galaxies. Calorimeter-resolution X-ray spectroscopy is the ideal tool to understand this feedback mode, as it enables ...
Xin Xiang, Jon M. Miller, Ehud Behar, Rozenn Boissay-Malaquin, Laura Brenneman, Margaret Buhariwalla, Doyee Byun, Chris Done, Luigi Gallo, Dimitra Gerolymatou, Scott Hagen, Jelle Kaastra, Stephane Paltani, Frederick S. Porter, Richard Mushotzky, Hirofumi Noda, Missagh Mehdipour, Takeo Minezaki, Makoto Tashiro, Abderahmen Zoghbi   +19 more
doaj   +1 more source

On the Extremely X-Ray Variable Active Galactic Nuclei in the XMM-LSS Field

The Astrophysical Journal
We present a systematic investigation of extremely X-ray variable active galactic nuclei (AGNs) in the ≈5.3 deg ^2 XMM-SERVS XMM-LSS region. Eight variable AGNs are identified with rest-frame 2 keV flux density variability amplitudes around 6–12.
Zijian Zhang, Bin Luo, Linhua Jiang, W. N. Brandt, Jian Huang, Qingling Ni   +5 more
doaj   +1 more source

Redshifted Iron Emission and Absorption Lines in the Chandra X-Ray Spectrum of Centaurus A

The Astrophysical Journal
Cen A hosts the closest active galactic nucleus to the Milky Way, which makes it an ideal target for investigating the dynamical processes in the vicinity of accreting supermassive black holes.
David Bogensberger, Jon Miller, Elias Kammoun, Richard Mushotzky, Laura Brenneman, W. N. Brandt, Edward M. Cackett, Andrew Fabian, Jelle Kaastra, Shashank Dattathri, Ehud Behar, Abderahmen Zoghbi   +11 more
doaj   +1 more source

"Fermi" bubbles are bursting from our galaxy. Their origins remain a mystery. [PDF]

Proc Natl Acad Sci U S A, 2023
Mann A.
europepmc   +1 more source

X-ray emission mechanisms in active galactic nuclei

, 2016
Active Galactic Nuclei (AGN) are compact regions at the centre of active galaxies which are visible across the full electromagnetic spectrum. Their radiation comes from the accretion of matter onto a supermassive black hole. They are particularly bright in X-rays, showing several components in their spectra.
openaire   +3 more sources

First Observational Evidence for an Interconnected Evolution between Time Lag and QPO Frequency among AGNs

The Astrophysical Journal Letters
Quasiperiodic oscillations (QPOs) have been widely observed in black hole X-ray binaries (BHBs), which often exhibit significant X-ray variations. Extensive research has explored the long-term evolution of the properties of QPOs in BHBs.
Ruisong Xia, Hao Liu, Yongquan Xue
doaj   +1 more source

Cosmic X-ray Background from Early Active Galactic Nuclei [PDF]

, 1989
A. A. Zdziarski
openalex   +1 more source