Results 81 to 90 of about 132,127 (94)
The Multitude of Unresolved Continuum Sources at 1.6 microns in Hubble Space Telescope images of Seyfert Galaxies [PDF]
, 1999 We examine 112 Seyfert galaxies observed by the Hubble Space Telescope (HST) at 1.6 microns. We find that ~50% of the Seyfert 2.0 galaxies which are part of the Revised Shapeley-Ames (RSA) Catalog or the CfA redshift sample contain unresolved continuum sources at 1.6 microns. All but a couple of the Seyfert 1.0-1.9 galaxies display unresolved continuum
arxiv +1 more source
Narrow Line Seyfert 1 Galaxies and the Evolution of Galaxies & Active Galaxies [PDF]
, 2000 Narrow Line Seyfert 1 galaxies (NLS1s) are intriguing due to their continuum as well as emission line properties. The observed peculiar properties of the NLS1s are believed to be due to accretion rate close to Eddington limit. As a consequence, for a given luminosity, NLS1s have smaller black hole (BH) masses compared to normal Seyfert galaxies. Here
arxiv +1 more source
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
doaj +1 more source
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
Parsec-scale Nuclear Radio Structures in Seyfert Galaxies [PDF]
arXiv, 2018 Radio outflows of extents ranging from a few parsecs to a few kiloparsecs are present in Seyfert and LINER galaxies that make up the `radio-quiet' AGN class. AGN jets and/or starburst superwinds have been suggested to produce these outflows. We present a brief review of radio outflows in Seyfert and LINER galaxies on different spatial scales. Very long
arxiv
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
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
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
doaj +1 more source
INTEGRAL and the Unified Model of AGN [PDF]
arXiv, 2011 According to the unified model, the differences observed in different classes of AGN are due to anisotropic obscuration. This implies that in the hard X-rays, at energies where the radiation can pierce the obscuring material, the average spectral characteristics of different classes of AGN should be the same.
arxiv
The Astrophysical JournalHard X-ray-selected samples of active galactic nuclei (AGN) provide one of the cleanest views of supermassive black hole accretion but are biased against objects obscured by Compton-thick gas column densities of N _H > 10 ^24 cm ^−2 .
Peter G. Boorman +35 more
doaj +1 more source