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相关论文: The long-term millimeter activity of active galact…

200 篇论文

8.4-GHZ radio imaging study of an optically selected sample of early type Seyfert galaxies; comparison of images taken at two epochs reveals possible variation in the nuclear radio flux density in five of them over a seven year period. It…

宇宙学与河外天体物理 · 物理学 2011-07-25 C. G. Mundell , N. Nagar , P. Ferruit

Aims: We used data from the 58 month long, continuous Swift/Burst Alert Telescope (BAT) observations of the five brightest Seyfert galaxies at hard X-rays, to study their flux and spectral variability in the 20-100 keV energy band. The…

高能天体物理现象 · 物理学 2015-05-30 M. D. Caballero-Garcia , I. E. Papadakis , F. Nicastro , M. Ajello

We report on candidate active galactic nuclei (AGN) discovered during the monitoring of $\sim$500 bright (r < 18 mag) galaxies over several years with the Kepler Mission. Most of the targets were sampled every 30 minutes nearly continuously…

高能天体物理现象 · 物理学 2015-12-09 Edward J. Shaya , Robert Olling , Richard Mushotzky

We discuss preliminary results from a joint XMM-Newton and NuSTAR monitoring program on the active galactic nucleus NGC 4593, consisting of 5x20 ks observations, spaced by two days, performed in January 2015. The source is found to be…

高能天体物理现象 · 物理学 2016-05-25 F. Ursini , P. -O. Petrucci , G. Matt , S. Bianchi , M. Cappi , B. De Marco , A. De Rosa , J. Malzac , G. Ponti

GSN 069 is an optically identified very low-mass AGN which shows supersoft X-ray emission. The source is known to exhibit huge X-ray outburst, with flux increased by more than a factor of ~240 compared to the quiescence state. We report its…

高能天体物理现象 · 物理学 2018-09-12 X. W. Shu , S. S. Wang , L. M. Dou , N. Jiang , J. X. Wang , T. G. Wang

The origin of the astrophysical neutrino flux reported by the IceCube Collaboration remains an open question. In this study, we use three years of publicly available IceCube data to search for evidence of neutrino emission from the blazars…

高能天体物理现象 · 物理学 2021-03-17 Daniel Smith , Dan Hooper , Abigail Vieregg

We have obtained new spectropolarimetric observations at visible wavelengths of the changing-look active galactic nucleus (AGN) Mrk 1018. The AGN direct spectrum shows an extremely weak continuum with faint broad H$\beta$ and H$\alpha$…

星系天体物理 · 物理学 2021-01-04 Damien Hutsemékers , Beatriz Agís González , Frédéric Marin , Dominique Sluse

We use nine years of gamma-ray data provided by the Fermi Large Area Telescope (LAT) to systematically study the light curves of more than two thousand active galactic nuclei (AGN) included in recent Fermi-LAT catalogs. Ten different…

高能天体物理现象 · 物理学 2020-07-01 P. Peñil , A. Domínguez , S. Buson , M. Ajello , J. Otero-Santos , J. A. Barrio , R. Nemmen , S. Cutini , B. Rani , A. Franckowiak , E. Cavazzuti

The emission line luminosity function of active galactic nuclei (AGN) is measured from about 3000 AGN included in the main galaxy sample of the Sloan Digital Sky Survey within a redshift range of $0<z<0.15$. The $\Ha$ and [OIII]$\lambda…

We analyse optical datacubes of the inner kiloparsec of 30 local ($z\le0.02$) active galactic nuclei (AGN) hosts that our research group, AGNIFS, has collected over the past decade via observations with the integral field units of the…

We analyze 18 sources that were found to show interesting properties of periodicity, very soft spectra and/or large long-term variability in X-rays in our project of classification of sources from the 2XMMi-DR3 catalog but were poorly…

高能天体物理现象 · 物理学 2015-06-17 Dacheng Lin , Natalie A. Webb , Didier Barret

We present a comprehensive long-term multi-wavelength study of the active galactic nucleus (AGN) NGC 3822, based on 17 years (2008 to 2025) of X-ray, ultraviolet (UV), and optical observations.The dataset includes observations from Swift,…

Aims: Active Galactic Nuclei are known to be variable throughout the electromagnetic spectrum. An energy domain poorly studied in this respect is the hard X-ray range above 20 keV. Methods: The first 9 months of the Swift/BAT all-sky survey…

天体物理学 · 物理学 2015-05-13 V. Beckmann , S. D. Barthelmy , T. J. -L. Courvoisier , N. Gehrels , S. Soldi , J. Tueller , G. Wendt

We present the final observations of a complete sample of 37 radio galaxies from the Third Cambridge Catalog (3C) with redshift <0.3 and declination <20 degrees obtained with the VLT/MUSE optical integral field spectrograph. These data were…

Time variability of the photon flux is a known feature of active galactic nuclei (AGN) and in particular of blazars. The high frequency peaked BL Lac (HBL) object PKS 2155-304 is one of the brightest sources in the TeV band and has been…

高能天体物理现象 · 物理学 2019-08-14 Jill Chevalier , Max Anton Kastendieck , Frank Rieger , Gilles Maurin , Jean-Philippe Lenain , Giovanni Lamanna

We report the discovery of two sources at z=3.867 and z=3.427 that exhibit powerful starburst and AGN activities. They benefit from data from radio to X rays from the CFHTLS-D1/SWIRE/XMDS surveys. Follow-up optical and near-infrared…

We present results from a joint Xmm-Newton/NuSTAR monitoring of the Seyfert 1 NGC 4593, consisting of 5x20 ks simultaneous observations spaced by two days, performed in January 2015. The source is variable, both in flux and spectral shape,…

高能天体物理现象 · 物理学 2016-08-17 F. Ursini , P. -O. Petrucci , G. Matt , S. Bianchi , M. Cappi , B. De Marco , A. De Rosa , J. Malzac , A. Marinucci , G. Ponti , A. Tortosa

We report a serendipitous discovery of six very low-luminosity active galactic nuclei (AGNs) only by optical variability in one-month baseline. The detected flux variability is ~ 1-5% of the total luminosity of host galaxies. Careful…

天体物理学 · 物理学 2009-11-10 Tomonori Totani , Takahiro Sumi , George Kosugi , Naoki Yasuda , Mamoru Doi , Takeshi Oda

We analyze the wavelength-dependent variability of a sample of spectroscopically confirmed active galactic nuclei (AGN) selected from near-UV ($NUV$) variable sources in the GALEX Time Domain Survey that have a large amplitude of optical…

We present a study of the extended radio emission in a sample of 8434 low redshift (z < 0.35) broad line active galactic nuclei (AGN) from the Sloan Digital Sky Survey (SDSS). To calculate the jet and lobe contributions to the total radio…

宇宙学与河外天体物理 · 物理学 2015-05-20 Stephen E. Rafter , D. Michael Crenshaw , Paul J. Wiita