Results 91 to 100 of about 125,183 (220)

Very high energy gamma-ray emission of NGC 1275 and 3c382 and the possible activity nature of the Seyfert Galaxies

open access: yesEPJ Web of Conferences, 2013
Galaxy NGC 1275 is the central dominant galaxy of the Perseus Cluster of Galaxies and is of Seyfert galaxy class. NGC 1275 is known as powerful X-ray and radio source.
Sinitsyna V.Y., Sinitsyna V.G.
doaj   +1 more source

Far-infrared properties of optically-selected quasars and Seyfert galaxies [PDF]

open access: yes, 1987
Pointed IRAS observations and ground based observations are used to determine the infrared properties of optically selected galaxies and quasars. The use of complete, unbiased, optically selected samples means that statistical tests can be applied to ...
Edelson, R. A., Malkan, M. A.
core  

Neutrino signal from Seyfert galaxies [PDF]

open access: yes
International audienceIceCube collaboration has previously reported an evidence for neutrino signal from a Seyfert galaxy NGC 1068. This may suggest that all Seyfert galaxies emit neutrinos.
Neronov, Andrii   +6 more
core   +1 more source

A Systematic Search for Active Galactic Nuclei Obscuration Variability in the Chandra Archive

open access: yesThe Astrophysical Journal
The nature of the obscuring material in active galactic nuclei (AGN) can be studied by measuring changes in the line-of-sight column density, N _H,LOS , over time. This can be accomplished by monitoring AGN over long periods of time and at all timescales.
Isaiah S. Cox   +7 more
doaj   +1 more source

Seyfert galaxies in the infrared

open access: yes, 1997
This thesis contains complementary aspects of the Seyfert phenomenon, each of which is analysed to bring a better understanding of present unification theories.
Ruiz-Nishiky, Milagros
core   +1 more source

IceCube Search for Neutrino Emission from X-Ray Bright Seyfert Galaxies

open access: yesThe Astrophysical Journal
The recent IceCube detection of TeV neutrino emission from the nearby active galaxy NGC 1068 suggests that active galactic nuclei (AGNs) could make a sizable contribution to the diffuse flux of astrophysical neutrinos. The absence of TeV γ -rays from NGC
R. Abbasi   +424 more
doaj   +1 more source

Grandeurs spectrophotométriques concernant des galaxies Seyfert

open access: yes, 1976
Le calcul des grandeurs spectrophotométriques : gradients (Φ0, 40,Φ0, 50), pentes (G0, 40 G0, 50) et différences des log10 des densités de flux (Δ = log10 F0,50 — log10 F0,40) a été fait pour 66 galaxies Seyfert et a conduit à l'établissement de deux ...
Edgard Vandekerkhove   +1 more
core   +1 more source

Emission line profiles and X-ray observations of broad and narrow line Seyfert 1 galaxies

open access: yes, 2011
Narrow Line Seyfert 1 galaxies represent a distinct category in the larger family of Type 1 Active Galactic Nuclei. The occurrence of emission line profiles not broader than 2000 km/s, combined with luminosity estimates comparable to those of their broad
CIROI, STEFANO   +5 more
core  

Evidence for Neutrino Emission from X-Ray Bright Seyfert Galaxies in the Southern Hemisphere Using Enhanced Starting Track Events with IceCube

open access: yesThe Astrophysical Journal Letters
IceCube recently reported the observation of TeV neutrinos from the nearby Seyfert galaxy NGC 1068, and the corresponding neutrino flux is significantly higher than the upper limit implied by observations of GeV–TeV gamma rays.
R. Abbasi   +430 more
doaj   +1 more source

The shortest detected intra-day variability of active galactic nuclei in the TESS survey

open access: yesAstronomy & Astrophysics
Context. Active galactic nuclei (AGNs) are known to be variable in almost all wavelengths and timescales. The shortest AGN variability timescale can be used to probe the smallest scale structures within AGNs. Aims. We aim to measure the shortest detected
Yuk Heechan   +2 more
doaj   +1 more source

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