Results 31 to 40 of about 22,607 (224)
Acta Polytechnica CTU Proceedings, 2014 We present systematic X-ray data analysis of the Seyfert galaxies observed by Suzaku to study origin of their hard X-ray (2 - 40 keV) variations. In particular, we examine if the "Variable Partial Covering (VPC) model" proposed by Miyakawa, Ebisawa and ...
Ken Ebisawa +3 more
doaj +1 more source
A complete sample of Seyfert galaxies selected at 1/4 keV [PDF]
, 2001 We have used the ROSAT Bright Source Catalogue to extract a complete sample of sources selected in the band from 0.1-0.4 keV. This 1/4 keV-selected sample is comprised of 54 Seyfert galaxies, 25 BL Lacertae objects, 4 clusters and 27 Galactic stars or ...
Edelson, R. +4 more
core +3 more sources
Recent Results from the SAFIR Project
Acta Polytechnica CTU Proceedings, 2014 The "Seyfert and star formation Activity in the Far-Infrared" (SAFIR) project is aimed at studying the physical nature of the nuclear IR emission and star formation properties of a small sample of nearby Seyfert galaxies observed with the PACS and SPIRE ...
M. Sánchez-Portal +18 more
doaj +1 more source
Radial Velocity Offsets Due to Mass Outflows and Extinction in Active Galactic Nuclei [PDF]
, 2009 We present a study of the radial velocity offsets between narrow emission lines and host galaxy lines (stellar absorption and H I 21-cm emission) in Seyfert galaxies with observed redshifts less than 0.043.
Antonucci +49 more
core +1 more source
The Astrophysical Journal, 2001 It is known that the spectral energy distribution (SED) of the nuclear radiation of narrow-line Seyfert 1 galaxies (NLS1s) has different shapes with respect to that of ordinary broad-line Seyfert 1 galaxies (BLS1s), particularly in wavelengths of X-ray.
Nagao, T., Murayama, T., Taniguchi, Y.
openaire +2 more sources
Unabsorbed Seyfert 2 galaxies [PDF]
Astronomy & Astrophysics, 2002 We present a sample of 17 type 2 Seyfert galaxies which have an X-ray column density lower than 10^{22} cm^{-2}. The Compton thin nature of these sources is strongly suggested by isotropic indicators. We estimate the fraction of these sources to be in the range of 10% - 30% of the population of type 2 Seyfert galaxies.
Panessa F., Bassani L.
openaire +3 more sources
What We Talk about When We Talk about Blazars?
Frontiers in Astronomy and Space Sciences, 2017 After the discovery of powerful relativistic jets from Narrow-Line Seyfert 1 Galaxies, and the understanding of their similarity with those of blazars, a problem of terminology was born.
Luigi Foschini
doaj +1 more source
Optical Properties of Two Complementary Samples of Intermediate Seyfert Galaxies
Physics, 2023 We present first results of the analysis of optical spectra of two complementary samples of Seyfert galaxies (Seyferts). The first sample was extracted from a selection of the 4th Fermi Gamma-ray Large Area Telescope (4FGL) catalog and consists of 11 γ ...
Benedetta Dalla Barba +5 more
doaj +1 more source
Large-Scale Environment Properties of Narrow-Line Seyfert 1 Galaxies at z < 0.4
Frontiers in Astronomy and Space Sciences, 2017 The large-scale environment is believed to affect the evolution and intrinsic properties of galaxies. It offers a new perspective on narrow-line Seyfert 1 galaxies (NLS1) which have not been extensively studied in this context before.
Emilia Järvelä +5 more
doaj +1 more source
The Seyfert Population in the Local Universe
, 2003 The magnitude-limited catalog of the Southern Sky Redshift Survey (SSRS2), is used to characterize the properties of galaxies hosting Active Galactic Nuclei.
Christopher N. A. Willmer +13 more
core +1 more source