Results 11 to 20 of about 512 (184)
Extreme accretion events: TDEs and changing‐look AGN
Astronomische Nachrichten, Volume 344, Issue 4, May 2023., 2023 Abstract We present a review of the topics of X‐ray stellar tidal disruption events (TDEs) and changing‐look active galactic nuclei (AGN). Stars approaching a supermassive black hole (SMBH) can be tidally disrupted and accreted. TDEs were first discovered in the X‐ray regime and appear as luminous, giant‐amplitude flares from inactive galaxies.
S. Komossa, D. Grupe
wiley +1 more source
Does Feedback from Supermassive Black Holes Coevolve with the Host in Type 2 Quasars?
The Astrophysical Journal, 2023 The feedback from the accretion of central supermassive black holes (SMBHs) is a hot topic in the coevolution of SMBHs and their host galaxies. By tracing the large-scale outflow using the line profile and bulk velocity shift of [O iii ] λ 5007, the ...
S. Jin +7 more
doaj +1 more source
Astronomische Nachrichten, Volume 344, Issue 4, May 2023., 2023 Abstract Radiation‐magnetohydrodynamic simulation of the active galactic nuclei predicts the presence of the strong accretion disk wind, which gets unstable far from the central region and turns into gas clumps. These inner wind and outer clumps may be actually observed as the ultrafast outflows (UFOs) and the clumpy absorbers, respectively.
Takuya Midooka +2 more
wiley +1 more source
Peaked sources and narrow‐line Seyfert 1s: A love story
Astronomische Nachrichten, Volume 342, Issue 9-10, Page 1066-1070, November-December 2021., 2021 Abstract The first similarities between peaked sources (PS) and narrow‐line Seyfert 1 (NLS1) galaxies were noticed already 20 years ago. Nowadays, it is known that several sources can share both classifications, and that part of the parent population of γ‐ray emitting NLS1s could be hiding among PS.
Marco Berton, Emilia Järvelä
wiley +1 more source
Helical Structures in Seyfert Galaxies [PDF]
International Astronomical Union Colloquium, 2002 Abstract Seyfert galaxies with Z-shaped emission filaments in the Narrow Line Region (NLR) are considered. We assume that observable Z-shaped structures and the velocity pattern of the NLR may be explained as tri-dimensional helical waves in the ionization cone.
Moiseev, A. V. +4 more
openaire +2 more sources
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
Nested and Single Bars in Seyfert and Non‐Seyfert Galaxies [PDF]
The Astrophysical Journal, 2002 33 pages, including 23 postscript figures, fixed a problem with deprojected position angle profiles and the resulting bar classifications and statistics numbers and figures and tables, to appear in ...
Laine, Seppo +3 more
openaire +2 more sources