Results 11 to 20 of about 9,238,867 (222)
Clustering of X-ray selected active galactic nuclei [PDF]
Monthly Notices of the Royal Astronomical Society, 1998 A total of 235 Active Galactic Nuclei (AGN) from two different soft X-ray surveys (the ROSAT Deep Survey -DRS- and the ROSAT International X-ray Optical Survey -RIXOS-) with redshifts between 0 and 3.5 are used to study the clustering of X-ray selected AGN and its evolution.
Carrera, Francisco J. +7 more
openaire +5 more sources
The distribution of galactic neighbours of X-ray-selected active galactic nuclei
Monthly Notices of the Royal Astronomical SocietyABSTRACT We combine X-ray data from the X-ray Multi-Mirror Mission 12th data release (4XMM DR12) and the extended ROentgen Survey with an Imaging Telescope Array (eROSITA) Final Equatorial-Depth Survey (eFEDS) early data release catalogues with the Galaxy and Mass Assembly spectroscopic galaxy survey to form a sample of 526 local ($0.05 ...
James R Jones +3 more
core +7 more sources
X-Ray Eclipses of Active Galactic Nuclei [PDF]
The Astrophysical Journal, 2017 Abstract X-ray variation is a ubiquitous feature of active galactic nuclei (AGNs); however, its origin is not well understood. In this paper, we show that the X-ray flux variations in some AGNs, and correspondingly, the power spectral densities (PSDs) of the variations, may be interpreted as being caused by absorptions of eclipsing ...
Fupeng Zhang, Qingjuan Yu, Youjun Lu
openaire +2 more sources
Rapid X-Ray Variability in Active Galactic Nuclei [PDF]
Symposium - International Astronomical Union, 1986 SummaryRecent EXOSAT observations of active galactic nuclei are presented. Unlike earlier X-ray satellites (all of which flew in low earth orbit), the deep orbit of EXOSAT allows long continuous observations of celestial X-ray sources, uninterrupted by earth occultation etc.
P. Barr +4 more
openaire +1 more source
Search for X-ray occultations in active galactic nuclei [PDF]
Monthly Notices of the Royal Astronomical Society, 2014 Accepted for publication in MNRAS. 15 pages, 7 figures. Table 2 not included, will be available in the published version.
G. Torricelli Ciamponi +3 more
openaire +2 more sources
X-ray absorption and reflection in active galactic nuclei [PDF]
The Astronomy and Astrophysics Review, 2009 Accepted for publication in the Astronomy and Astrophysics Review. 58 pages, 9 figures.
Turner, T, Miller, L
openaire +3 more sources
The Astrophysical Journal, 2023 We report on the 2019 XMM-Newton+NuSTAR monitoring campaign of the Seyfert galaxy NGC 2992, observed at one of its highest flux levels in the X-rays.
Alfredo Luminari +10 more
doaj +1 more source
Variability and the X-ray/UV ratio of active galactic nuclei [PDF]
Astronomy and Astrophysics, 2010 16 pages, 10 figures, 1 table.
VAGNETTI, FAUSTO +3 more
openaire +4 more sources
X-Ray Variability of Active Galactic Nuclei [PDF]
Highlights of Astronomy, 1983 X-ray variability of active galactic nuclei is commonplace on scales from days to years. It also occurs, although rarely, on time scales as short as 200 seconds. Both these statements must be strongly qualified by the irregularity and insensitivity of the available observations. In the X-rays we expect that we are seeing deep within the active nucleus,
Daniel A. Schwartz +2 more
openaire +1 more source
The Astrophysical Journal, 2023 “Changing-look active galactic nuclei” (CLAGNs) are known to change their apparent types between types 1 and 2, usually accompanied by a drastic change in their luminosity on timescales of years.
Hirofumi Noda +13 more
doaj +1 more source