Results 121 to 130 of about 50,208 (269)

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

Modeling the X-ray fractional variability spectrum of Active Galactic Nuclei using multiple flares [PDF]

, 2006
Using Monte-Carlo simulations of X-ray flare distributions across the accretion disk of active galactic nuclei (AGN), we obtain modeling results for the energy-dependent fractional variability amplitude.
Czerny, B., Dovciak, M., Goosmann, R. W., Karas, V., Mouchet, M., Ponti, G.   +5 more
core   +3 more sources

Radiation induced by relativistic electron showers in the X-ray spectrum of Active Galactic Nuclei [PDF]

, 2005
A. Antonicci, Ana I. Gómez de Castro
openalex   +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

A complete X-ray sample of the high latitude sky from HEAO-1 A-2: log N lo S and luminosity functions [PDF]

An experiment was performed in which a complete X-ray survey of the 8.2 steradians of the sky at galactic latitudes where the absolute value of b is 20 deg down to a limiting sensitivity of 3.1 x ten to the minus 11th power ergs/sq cm sec in the 2-10 ...
Boldt, E. A., Holt, S. S., Marshall, F. E., Mushotzky, R. F., Piccinotti, G., Serlemitsos, P. J., Shafer, R. A.   +6 more
core   +1 more source

Ensemble spectral variability study of Active Galactic Nuclei from the XMM-Newton serendipitous source catalogue

, 2016
The variability of the X-ray spectra of active galactic nuclei (AGN) usually includes a change of the spectral slope. This has been investigated for a small sample of local AGNs by Sobolewska and Papadakis, who found that slope variations are well ...
Middei, Riccardo, Serafinelli, Roberto, Vagnetti, Fausto   +2 more
core   +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

ABSTRACTS

Precision Radiation Oncology, EarlyView.
wiley   +1 more source

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

On the occupation of X-ray-selected galaxy groups by radio active galactic nuclei since z = 1.3 [PDF]

, 2011
V Smolcić, A. Finoguenov, G. Zamorani, E. Schinnerer, M Tanaka, S. Giodini, N. Scoville   +6 more
openalex   +1 more source