Results 11 to 20 of about 132,127 (94)
Estimate of SMBH Spin for Narrow-Line Seyfert 1 Galaxies
Universe, 2023 We estimated the spin values of the supermassive black holes (SMBHs) of the active galactic nuclei (AGN) for a large set of Narrow Line Seyfert 1 (NLS1) galaxies assuming the inclination angle between the line of sight and the axis of the accretion disk ...
Mikhail Piotrovich +2 more
doaj +1 more source
Iraqi Journal of Physics, 2021 An optical spectroscopic study is reported in this article to study the correlation between the supermassive black hole (SMBH) and the star formation rate (SFR) for a sample of Seyfert galaxies type (I and II).
Salwa H. Kareem, Yasir Ezzuldeen Rashed
doaj +1 more source
Decomposition of the central structure of NGC 2273 in the NIR: A case study
Astronomische Nachrichten, Volume 344, Issue 10, December 2023., 2023 Abstract The Seyfert 2 galaxy NGC 2273 is a prime target to explore how active nuclei can be fed. It has a star‐forming innermost nuclear ring with a radius of 0.33kpc from where material may be funneled to the supermassive black hole in its center. In this article, we discuss high‐resolution adaptive optics aided JHKs images of NGC 2273 taken with the
L. Schey +13 more
wiley +1 more source
A tool to understand emission mechanisms of blazars through their high‐energy gamma‐ray emission
Astronomische Nachrichten, Volume 344, Issue 6, August 2023., 2023 The blazar SED is characterized by two energy components. Evidence suggests that the low‐energy component is generated by the synchrotron mechanism, but for the high‐energy component, the mechanism is still uncertain. Two main models have been proposed to explain this emission. According to the leptonic model, a correlation between the emission of both
Mabel Osorio +3 more
wiley +1 more source
Unraveling the enigmatic soft x‐ray excess: Current understanding and future perspectives
Astronomische Nachrichten, Volume 344, Issue 6, August 2023., 2023 Abstract This article explores various theoretical models proposed to explain the soft x‐ray excess phenomenon, including warm Comptonization, ionized reflection models, and ionized outflowing disc winds. The soft x‐ray excess is better understood thanks to crucial observations made by ROSAT, XMM‐Newton, and eROSITA.
Thomas Boller
wiley +1 more source
Searching for overlooked TDEs in the 4XMM catalogue
Astronomische Nachrichten, Volume 344, Issue 4, May 2023., 2023 Abstract Tidal disruption events (TDEs) are usually discovered as bright transients, either in the X‐ray or optical/UV band. These events are often characterized by a “super‐soft” emission in the X‐ray band, which has not been observed in any other extragalactic source, with few exceptions (novae and supersoft active galactic nuclei, AGN), which can ...
Andrea Sacchi +2 more
wiley +1 more source
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
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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
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