Results 91 to 100 of about 261,296 (275)

A New Sample of Gamma-Ray Emitting Jetted Active Galactic Nuclei

Universe, 2022
We considered the fourth catalog of gamma-ray point sources produced by the Fermi Large Area Telescope (LAT) and selected only jetted active galactic nuclei (AGN) or sources with no specific classification, but with a low-frequency counterpart. Our final
Luigi Foschini, Matthew L. Lister, Heinz Andernach, Stefano Ciroi, Paola Marziani, Sonia Antón, Marco Berton, Elena Dalla Bontà, Emilia Järvelä, Maria J. M. Marchã, Patrizia Romano, Merja Tornikoski, Stefano Vercellone, Amelia Vietri   +13 more
doaj   +1 more source

A Composite Seyfert 2 X-ray Spectrum: Implications for the Origin of the Cosmic X-ray Background [PDF]

, 2001
We present a composite 1-10 keV Seyfert 2 X-ray spectrum, derived from ASCA observations of a distance-limited sample of nearby galaxies. All 29 observed objects were detected.
Aaron J. Barth, Alexei V. Filippenko, Antonucci R., Awaki H., Cappi M., Comastri A., Edward C. Moran, Gendreau K. C., Laura E. Kay, Madau P., Marc Davis, Miyaji T., Schmidt M., Setti G.   +13 more
core   +2 more sources

On the X-ray, optical emission line and black hole mass properties of local Seyfert galaxies ! [PDF]

, 2006
We investigate the relation between X-ray nuclear emission, optical emission line luminosities and black hole masses for a sample of 47 Seyfert galaxies. The sample, which has been selected from the Palomar optical spectroscopic survey of nearby galaxies
F. Panessa, L. Bassani, M. Cappi, M. Dadina, X. Barcons, F. J. Carrera, Luis C. Ho, K. Iwasawa   +7 more
semanticscholar   +1 more source

The Relative Contributions of Accretion Disk versus Jet to the Optical and Mid-infrared Variability of Seyfert Galaxies

The Astrophysical Journal
We performed a comprehensive analysis of flux and color variability in a redshift-matched sample of Seyfert galaxies, comprising 23 gamma-ray-detected narrow-line Seyfert 1 galaxies (gNLS1s), 190 non-gamma-ray-detected narrow-line Seyfert 1 galaxies ...
Vineet Ojha, Xue-Bing Wu, Luis C. Ho
doaj   +1 more source

Optical and infrared spectrophotometry of 18 Markarian galaxies [PDF]

, 1976
Slit spectra, spectrophotometric scans and infrared broad band observations are presented. Eight of the program galaxies can be classified as Seyfert galaxies.
Becklin, E. E., Neugebauer, G., Oke, J. B., Searle, L.   +3 more
core   +1 more source

Mildly Suppressed Star Formation in Central Regions of MaNGA Seyfert Galaxies

, 2018
Negative feedback from accretion onto super-massive black holes (SMBHs), that is to remove gas and suppress star formation in galaxies, has been widely suggested.
Bing, Longji, Bizyaev, Dmitry, Chen, Yanmei, Drory, Niv, Maiolino, Roberto, Pan, Kaike, Riffel, Rogemar A., Riffel, Rogério, Shi, Yong, Sánchez, Sebastián F., Wylezalek, Dominika   +10 more
core   +1 more source

INFRARED SPECTRAL ENERGY DISTRIBUTIONS OF SEYFERT GALAXIES: SPITZER SPACE TELESCOPE OBSERVATIONS OF THE 12 μm SAMPLE OF ACTIVE GALAXIES [PDF]

, 2010
The mid-infrared spectral energy distributions (SEDs) of 83 active galaxies, mostly Seyfert galaxies, selected from the extended 12 μm sample are presented.
J. Gallimore, A. Yzaguirre, A. Yzaguirre, J. Jakoboski, J. Jakoboski, M. J. Stevenosky, M. J. Stevenosky, D. Axon, D. Axon, S. Baum, C. Buchanan, M. Elitzur, M. Elvis, C. O’Dea, A. Robinson   +14 more
semanticscholar   +1 more source

High-energy Electromagnetic, Neutrino, and Cosmic-Ray Emission by Stellar-mass Black Holes in Disks of Active Galactic Nuclei

The Astrophysical Journal, 2023
Some Seyfert galaxies are detected in high-energy gamma rays, but the mechanism and site of gamma-ray emission are unknown. Also, the origins of the cosmic high-energy neutrino and MeV gamma-ray backgrounds have been veiled in mystery since their ...
Hiromichi Tagawa, Shigeo S. Kimura, Zoltán Haiman   +2 more
doaj   +1 more source

A variability study of the Seyfert 2 galaxy NGC 6300 with XMM-Newton

, 2005
We present the results of timing analysis of the XMM-Newton observation of the Seyfert 2 galaxy NGC 6300. The hard X-ray spectrum above 2 keV consists of a Compton-thin-absorbed power law, as is often seen in Seyfert 2 galaxies. We clearly detected rapid
Antonucci R. R. J., Awaki H., Belloni T., Busko I. C., Chiho Matsumoto, Dirk Grupe, Hirokatsu Murakami, Hisamitsu Awaki, Karen M. Leighly, Kawaguchi T., Kiyoshi Hayashida, Padovani P., Papadakis I. E., Timmer J.   +13 more
core   +1 more source

An atlas of Calcium triplet spectra of active galaxies [PDF]

, 2005
We present a spectroscopic atlas of active galactic nuclei covering the region around the 8498, 8542, 8662 Calcium triplet (CaT) lines. The sample comprises 78 objects, divided into 43 Seyfert 2s, 26 Seyfert 1s, 3 Starburst and 6 normal galaxies.
Asari, N. V., Delgado, R. M. Gonzalez, Fernandes, R. Cid, Garcia-Rissmann, A., Schmitt, H., Storchi-Bergmann, T., Vega, L. R.   +6 more
core   +2 more sources