Results 71 to 80 of about 262 (99)
The Astrophysical JournalWe present a detailed imaging analysis of 260 ks of subarcsecond resolution Chandra (ACIS-S) observations of the nearby Seyfert 2 galaxy NGC 5728. Our study focuses on the bright and diffuse soft X-ray emission within the galaxy's inner ∼1 kpc.
Anna Trindade Falcão +4 more
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UniverseIn terms of the variable nature of normal active galaxy nuclei (AGN) and luminous quasars, a so-called flux variation gradient (FVG) method has been widely utilized to estimate the underlying non-variable host galaxy fluxes.
Minxuan Cai +4 more
doaj +1 more source
The Disk Wind Contribution to the Gamma-Ray Emission from the Nearby Seyfert Galaxy GRS 1734−292
The Astrophysical JournalRadio-quiet Seyfert galaxies have been detected in GeV gamma rays by the Fermi Large Area Telescope (LAT), but the origin of much of this emission is unclear.
Nobuyuki Sakai +6 more
doaj +1 more source
The Astronomical Journal, 1982 As part of an ongoing program of measuring galaxy redshifts at Mount Hopkins observatory, we have discovered several previously unknown bright Seyfert galaxies. Most of the objects are of Seyfert type 2, but several are type 1 objects where the broad permitted line region is easily visible only for the H..cap alpha.. line.
M. Davis, W. F. Wyatt, J. P. Huchra
openaire +2 more sources
The radio properties of bright Seyfert galaxies
The Astrophysical Journal Supplement Series, 1990 The radio properties of a sample of 69 bright spectroscopically selected Seyfert galaxies, which suffers from little bias toward Markarian galaxies with strong UV excess. At variance with most of the earlier results, generally based on galaxy samples which are strongly biased toward the inclusion of Markarian objects, there is no clear evidence of a ...
GIURICIN G +3 more
openaire +3 more sources
Optical polarization of Seyfert galaxies
The Astrophysical Journal, 1988 Des mesures de la polarisation du continuum optique d'un echantillon de 19 galaxies de Seyfert ont ete effectuees. Elles sont accompagnees pour 9 d'entre-elles d'observations polarimetriques de la raie d'emission Hα.
Ian B. Thompson, Peter G. Martin
openaire +2 more sources
Optical Emission Lines and the X-Ray Properties of Type 1 Seyfert Galaxies
Open Astronomy, 2011 In this contribution we report on the study of the optical emission lines and X-ray spectra of a sample of Type 1 AGNs, collected from the SDSS database and observed by the XMM-Newton satellite.
La Mura G. +5 more
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X-ray Properties of Two Complementary Samples of Intermediate Seyfert Galaxies
UniverseWe present the X-ray spectral analysis of two complementary sets of intermediate Seyfert galaxies (ISs). Analyzing X-ray data, we estimate the hydrogen abundance NH and test its connection with the [O III] luminosity acquired from optical observations ...
Benedetta Dalla Barba +4 more
doaj +1 more source
Spectra of Seyfert galaxies and Seyfert galaxy candidates
The Astrophysical Journal, 1983 Donald E. Osterbrock, O. Dahari
openaire +2 more sources
Two 100 TeV Neutrinos Coincident with the Seyfert Galaxy NGC 7469
The Astrophysical JournalIn 2013, the IceCube collaboration announced the detection of a diffuse high-energy astrophysical neutrino flux. The origin of this flux is still largely unknown. The most significant individual source is the close-by Seyfert galaxy NGC 1068 at the 4.2 σ
Giacomo Sommani +3 more
doaj +1 more source