Results 141 to 150 of about 63,914 (268)
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. +5 more
core +3 more sources
Discovery of Changing-look Behavior in AGN NGC 3822: A Long-term Multiwavelength Study
The Astrophysical JournalWe present a comprehensive long-term multiwavelength study of the active galactic nucleus NGC 3822, based on 17 yr (2008–2025) of X-ray, ultraviolet (UV), and optical observations. The data set includes observations from Swift , XMM - Newton, and NuSTAR,
Narendranath Layek +9 more
doaj +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 +10 more
core
Force Multiplier Calculations for X-ray Binaries and Active Galactic Nuclei
, 2018 Motivated by the work done to explore the winds from hot stars (Lamers & Cassinelli 1999), we develop a method for self consistently calculating force multipliers for Type 1 and Type 2 active galactic nuclei (AGN), soft and hard start X-ray binaries ...
Dannen, Randall Cody
core +1 more source
A Systematic Search for Active Galactic Nuclei Obscuration Variability in the Chandra Archive
The Astrophysical JournalThe 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 +7 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. +6 more
core +1 more source
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. +4 more
core +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. +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 +16 more
openaire +2 more sources
On the Extended Soft X-Ray and Fe Kα Emission in NGC 1068
The Astrophysical JournalThe soft X-ray excess and Fe K α emission lines are widely observed in Seyfert galaxies, with their origin still in debate. We present a detailed spatially resolved image and spectral analysis of the Seyfert 2 galaxy NGC 1068 using high-resolution ...
Songbo Gao, Hongxing Yin, Shaoming Hu
doaj +1 more source