Results 111 to 120 of about 50,755 (263)

A Systematic Search for Active Galactic Nuclei Obscuration Variability in the Chandra Archive

The Astrophysical Journal
The nature of the obscuring material in active galactic nuclei (AGN) can be studied by measuring changes in the line-of-sight column density, N _H,LOS , over time. This can be accomplished by monitoring AGN over long periods of time and at all timescales.
Isaiah S. Cox, Núria Torres-Albà, Stefano Marchesi, Vittoria E. Gianolli, Xiurui Zhao, Marco Ajello, Indrani Pal, Ross Silver   +7 more
doaj   +1 more source

Black hole mass estimation from X-ray variability measurements in active galactic nuclei [PDF]

, 2004
M. Nikołajuk, I. E. Papadakis, B. Czerny   +2 more
openalex   +1 more source

Magnetic-Reconnection-Heated Corona Model: Implication of Hybrid Electrons for Hard X-ray Emission of Luminous Active Galactic Nuclei [PDF]

, 2023
J. Y. Liu, J. Mao, B. F. Liu
openalex   +1 more source

X-ray properties of Red Active Galactic Nuclei

, 2001
The Two Micron All Sky Survey (2MASS) is finding previously unidentified, luminous red active galactic nuclei (AGN). This new sample has a space density similar to, or greater than, previously known AGN, suggesting that a large fraction of the overall population has been missed. Chandra observations of a well-defined subset of these objects reveal that
Wilkes, Belinda J., Schmidt, Gary D., Cutri, Roc M., Ghosh, Himel, Hines, Dean C., Nelson, Brant, Smith, Paul   +6 more
openaire   +2 more sources

24 Micron Properties of X‐Ray–selected Active Galactic Nuclei

The Astrophysical Journal Supplement Series, 2004
We examine the 24 μm to X-ray color of 157 X-ray-selected active galactic nuclei (AGNs) as a function of X-ray obscuration and optical classification in the Chandra Deep Field-South. The sample consists of the Chandra hard-band detections with 2-8 keV flux above 10-15 ergs s-1 cm-2. A deep 24 μm mosaic obtained with Spitzer provides mid-infrared fluxes
Dean C. Hines, Dean C. Hines, Jane R. Rigby, M. J. Rieke, George H. Rieke, Roberto Maiolino, James Muzerolle, Karl D. Gordon, Roberto Gilli, Pablo G. Pérez-González, C. Papovich, E. Le Floc'h, A. Alonso-Herrero, Jane E. Morrison, Charles W. Engelbracht, Joannah L. Hinz, Kate Y. L. Su   +16 more
openaire   +2 more sources

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

The OPTX Project: Comparing the Optical and X-Ray Spectral Properties of Active Galactic Nuclei [PDF]

, 2009
Laura Trouille, A. J. Barger
openalex   +1 more source

Demography of obscured and unobscured AGN: prospects for a Wide Field X-ray Telescope

, 2010
We discuss some of the main open issues in the evolution of Active Galactic Nuclei which can be solved by the sensitive, wide area surveys to be performed by the proposed Wide Field X-ray Telescope mission.Comment: Proceedings of "The Wide Field X-ray ...
A. Comastri, C. Vignali, E. Lusso, F. Marulli, M. Brusa, P. Rosati, P. Tozzi, PAOLILLO, MAURIZIO, R. Gilli, S. Borgani, the WFXT team   +10 more
core  

X-raying the Winds of Luminous Active Galaxies

, 2009
We briefly describe some recent observational results, mainly at X-ray wavelengths, on the winds of luminous active galactic nuclei (AGNs). These winds likely play a significant role in galaxy feedback.
Brandt, W. N., Chartas, G., Gallagher, S. C., Gibson, R. R., Miller, B. P.   +4 more
core   +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