Results 61 to 70 of about 200 (175)

Spectroscopy of the galaxy components of N and Seyfert galaxies [PDF]

Publications of the Astronomical Society of the Pacific, 1987
Nuclear and off-nuclear spectra of nine active galaxies are presented. The sample consists of four Seyfert galaxies, two N galaxies, one Seyfert radio galaxy, and one liner/Seyfert 2 galaxy. All of the objects show continuum emission off the nucleus. Four clearly show absorption features from a stellar population.
Todd A. Boroson, J. B. Oke
openaire   +1 more source

Diagramme gradients -pentes concernant des galaxies et des quasars

, 1971
Pour le rayonnement de galaxies et de quasars, au repos ou de faible vitesse radiale, et les régions spectrales de 0,50μ et 0,34μ, un diagramme plan est présenté ; ses coordonnées rectangulaires sont les gradients spectrophotométriques ou bien les pentes
Edgard Vandekerkhove, Vandekerkhove, Edgard   +1 more
core   +1 more source

The soft excess of the NLS1 galaxy Mrk 359 studied with an XMM-Newton-NuSTAR monitoring campaign

, 2020
International audienceContext. Joint XMM-Newton and NuSTAR multiple exposures allow us to disentangle the different emission components of active galactic nuclei (AGNs) and to study the evolution of their different spectral features.
R. Middei, Tortosa, A., M. Clavel, A. Marinucci, A. Tortosa, Petrucci, P.O., Ursini, F., De Rosa, A., Petrucci, P. -O., Marinucci, A., G. Matt, Cappi, M., Matt, G., Middei, R., Clavel, M., P.-O. Petrucci, A. De Rosa, S. Bianchi, F. Ursini, Bianchi, S., M. Cappi   +20 more
core   +1 more source

The radio properties of bright Seyfert galaxies

The Astrophysical Journal Supplement Series, 1990
The radio properties of a sample of 69 bright spectroscopically selected Seyfert galaxies, which suffers from little bias toward Markarian galaxies with strong UV excess. At variance with most of the earlier results, generally based on galaxy samples which are strongly biased toward the inclusion of Markarian objects, there is no clear evidence of a ...
GIURICIN G, MARDIROSSIAN, FABIO, MEZZETTI, MARINO, BERTOTTI G.   +3 more
openaire   +2 more sources

Estimating the size of X-ray lamppost coronae in active galactic nuclei

, 2020
International audienceAims. We report estimates of the X-ray coronal size of active galactic nuclei in the lamppost geometry. In this commonly adopted scenario, the corona is assumed for simplicity to be a point-like X-ray source located on the axis of ...
Dovciak, M., P.-O. Petrucci, C. Done, Petrucci, P.-O., M. Dovčiak, W. Zhang, Ursini, F., F. Ursini, Zhang, W., Done, C., G. Matt, Matt, G.   +11 more
core   +2 more sources

A High Resolution Study of the LINER Galaxy NGC5218

, 2006
Low Ionisation Nuclear Emission-line Regions (LINERs)are found in one third of the galaxies in the local bright galaxy population. The LINERs typically recide in the central parts of their host galaxies, and occur in early type elliptical galaxies as ...
Olsson, Evert
core   +1 more source

A tentative classification of galaxies with active nuclei

, 1979
Proposes a bidimensional classification for galaxies with active nuclei (N galaxies, Seyfert galaxies, quasars and BL Lac objects) based on morphological and spectroscopic criteria.
Véron, P
core  

A deep X-ray view of the bare AGN Ark120. VI. Geometry of the hot corona from spectroscopic and polarization signatures [PDF]

, 2018
International audienceContext. The spectral shape of the hard X-ray continuum of Active Galactic Nuclei (AGN) can be ascribed to inverse Compton scattering of optical/UV seed photons from the accretion disc by a hot corona of electrons.
Marin, F., A. Marinucci, Nardini, E., Marinucci, A., Matt, G., Porquet, D., Braito, V., V. Braito, Tamborra, F., BRAITO, Valentina, D. Porquet, A. Lobban, F. Marin, Bianchi, S., J. Reeves, R. Middei, Tortosa, A., A. Tortosa, Lobban, A., F. Tamborra, G. Matt, Middei, R., Reeves, J., E. Nardini, S. Bianchi, NARDINI, EMANUELE   +25 more
core   +1 more source

Modeling optical and UV polarization of AGNs. V. Dilution by interstellar polarization and the host galaxy

, 2018
International audienceContext. One of the main challenges for polarimetric observations of active galactic nuclei (AGN) is to properly estimate the amount of parasitic light that contaminates the polarization signal.
Marin, F., F. Marin, Marin, Frédéric
core   +1 more source

The Research of Selected Active Galactic Nuclei‘s Photometric and Spectral Variability [PDF]

, 2019
Photometric and spectral observations of the active galactic nuclei NGC 1275, NGC 3227, and NGC 4151 are made with RTT-150 telescope in TUBITAK observatory (Turkey) during 2011—2012. These galaxies with active nuclei are Seyfert galaxies.
Efremova, P. D., Ефремова, П. Д.   +1 more
core