Results 11 to 20 of about 200 (175)

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, Eftychia Madika, Luca Ricci   +2 more
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., Afanasiev, V. L., Dodonov, S. N., Mustsevoi, V. V., Khrapov, S. S.   +4 more
openaire   +2 more sources

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

WISDOM Project - XVI. The link between circumnuclear molecular gas reservoirs and active galactic nucleus fuelling [PDF]

, 2023
We use high-resolution data from the millimetre-Wave Interferometric Survey of Dark Object Masses (WISDOM) project to investigate the connection between circumnuclear gas reservoirs and nuclear activity in a sample of nearby galaxies.
Davis, Timothy A, Bureau, Martin, Iguchi, Satoru, Williams, Thomas G., Elford, Jacob S, Liang, Fuheng, Elford, Jacob S., Liang, Fu Heng, Liu, Lijie, Davis, Timothy A., Cappellari, Michele, Gensior, Jindra, Liang, Fu-Heng, Williams, Thomas, Ruffa, Ilaria, Lu, Anan   +15 more
core   +1 more source

Jet Directions in Seyfert Galaxies [PDF]

The Astrophysical Journal, 2000
58 pages, 16 figures (included) and 5 tables.
Kinney, A. L., Schmitt, H. R., Clarke, C. J., Pringle, J. E., Ulvestad, J. S., Antonucci, R. R. J.   +5 more
openaire   +2 more sources

Tracking the Iron Ka line and the Ultra Fast Outflow in NGC 2992 at different accretion states [PDF]

, 2018
The Seyfert 2 galaxy NGC 2992 has been monitored eight times by XMM-Newton in 2010 and then observed again in 2013, while in 2015 it was simultaneously targeted by Swift and NuSTAR.

core   +1 more source

Seyfert galaxies and BeppoSAX [PDF]

Nuclear Physics B - Proceedings Supplements, 1999
The contributions that BeppoSAX is expected to give and, after one and a half year of operation, has already given to our knowledge of both type 1 and type 2 Seyfert galaxies are outlined and reviewed.
openaire   +3 more sources

Transient obscuration event captured in NGC 3227 - I. Continuum model for the broadband spectral energy distribution [PDF]

, 2021
International audienceFrom Swift monitoring of a sample of active galactic nuclei (AGN) we found a transient X-ray obscuration event in Seyfert-1 galaxy NGC 3227, and thus triggered our joint XMM-Newton, NuSTAR, and Hubble Space Telescope (HST ...
Brotherton, M., E. Behar, Mehdipour, M., Costantini, E, Petrucci, P.-O., Petrucci, PO, Kaastra, JS, Pinto, C, Di Gesu, L, Walton, DJ, Petrucci, P. -O., Matt, G., Paltani, S., Ursini, F, P.-O. Petrucci, Arav, N., Bianchi, S, Ponti, G, Kriss, GA, S. Kaspi, C. Pinto, Y. Wang, Walton, D.J., S. Paltani, Pinto, C., G. A. Kriss, Kriss, G. A., Kaastra, J., Petrucci, P., Mao, J., Pinto, C. search by orcid, Di Gesu, L., Branduardi-Raymont, G, G. Matt, de Marco, B., Walton, D. J., Behar, E., Ebrero, J, M. Brotherton, J. Ebrero, S. Bianchi, Kriss, G., F. Ursini, Wang, Y., J. S. Kaastra, S. Grafton-Waters, G. Branduardi-Raymont, Gesu, L., E. Costantini, B. De Marco, N. Arav, Matt, G, G. Ponti, Marco, B., L. Di Gesu, Costantini, E., Cappi, M., Gesu, L. Di, Mao, J, Ebrero, J., Kaastra, J.S., Behar, E, Bianchi, S., Arav, N, M. Cappi, Ponti, G., J. Mao, Grafton-Waters, S., Kaspi, S., Wang, Y, Branduardi-Raymont, G., Kaspi, S, Ursini, F., Cappi, M, Paltani, S, D. J. Walton, Walton, D., De Marco, B, Ursini, F. search by orcid, Mehdipour, M, Grafton-Waters, S, M. Mehdipour, Kriss, G.A., Brotherton, M, Kaastra, J. S., Marco, B. De   +85 more
core   +1 more source