Results 21 to 30 of about 125,183 (220)
Accretion mode and jet collimation in active galactic nuclei
Astronomische Nachrichten, Volume 342, Issue 9-10, Page 1071-1076, November-December 2021., 2021 Abstract In this article, we summarize our recent progress in observational studies of jet collimation in active galactic nuclei. We focus on the investigation of a relation between the properties of the collimation zone and the AGN accretion mode, recently proposed by Boccardi, B., Perucho, M., Casadio, C. et al., 2021, A&A, 647, A67.
Bia Boccardi +2 more
wiley +1 more source
1H 0707‐495: An AGN is dimming its X‐ray light
Astronomische Nachrichten, Volume 342, Issue 5, Page 708-714, June 2021., 2021 Abstract We report on one of the first science observations obtained during the Calibration and Verification phase of extended ROentgen Survey with an Imaging Telescope Array (eROSITA) aboard the Spectrum‐Roentgen‐Gamma (SRG) mission on the famous Narrow‐Line Seyfert 1 Galaxy 1H 0707‐495.
Thomas Boller
wiley +1 more source
Power Spectral Density Background Estimate and Signal Detection via the Multitaper Method
Journal of Geophysical Research: Space Physics, Volume 126, Issue 2, February 2021., 2021 Abstract We present a new spectral analysis method for the identification of periodic signals in geophysical time series. We evaluate the power spectral density with the adaptive multitaper method, a nonparametric spectral analysis technique suitable for time series characterized by colored power spectral density.
S. Di Matteo, N. M. Viall, L. Kepko
wiley +1 more source
Jet Directions in Seyfert Galaxies [PDF]
The Astrophysical Journal, 2000 58 pages, 16 figures (included) and 5 tables.
Kinney, A. L. +5 more
openaire +2 more sources
Constraining the contribution of Seyfert galaxies to the astrophysical diffuse neutrino flux using source population simulations [PDF]
EPJ Web of ConferencesRecently, the IceCube collaboration reported evidence for TeV neutrino emission from several nearby Seyfert galaxies that are intrinsically bright in X-rays, with the highest significance found for NGC 1068.
Saurenhaus Lena +2 more
doaj +1 more source
Intermediate Seyfert: optical spectroscopic characteristics [PDF]
, 2022 openActive Galactic Nuclei (AGN) are a particular class of galaxies characterized by a pretty luminous central region produced by an accreting disk. According to the Unified Model (UM) around this central structure we can recognize three regions: the ...
DALLA BARBA, BENEDETTA
core
X-RAY VARIABILITY STUDY OF POLAR SCATTERED SEYFERT1 GALAXIES
Acta Polytechnica, 2014 We study 12 Seyfert 1 galaxies with a high level of optical polarization. Optical light emerging from the innermost regions is predominantly scattered in a polar region above the central engine directly in our line of sight.
Tobias Beuchert +6 more
doaj +1 more source
Symposium - International Astronomical Union, 1982 Observations of sample of Markarian Seyferts with the VLA indicate that a large fraction possess linear radio structure on a scale of a few hundred parsecs to a few kiloparsecs. The radio components generally straddle the optical nucleus and several sources are simple doubles.
openaire +1 more source
Relativistic jets in narrow-line Seyfert 1 galaxies. New discoveries and open questions
EPJ Web of Conferences, 2013 Before the launch of the Fermi satellite only two classes of AGNs were known to produce relativistic jets and thus emit up to the γ-ray energy range: blazars and radio galaxies, both hosted in giant elliptical galaxies.
D’Ammando F. +4 more
doaj +1 more source
Looking for Signatures of AGN Feedback in Radio-Quiet AGN
Galaxies, 2023 In this article, we discuss the state of “AGN feedback” in radio-quiet (RQ) AGN. This study involves heterogeneous samples of nearby Seyfert and LINER galaxies as well as quasi-stellar objects (QSOs) that have been observed at low radio frequencies (few ∼
Preeti Kharb, Sasikumar Silpa
doaj +1 more source