English
Related papers

Related papers: Unconventional AGN from the SDSS

200 papers

We present the results of X-ray spectral analysis of 22 active galactic nuclei (AGNs) with a small scattering fraction selected from the Second XMM-Newton Serendipitous Source Catalogue using hardness ratios. They are candidates of buried…

Astrophysics of Galaxies · Physics 2014-11-20 Kazuhisa Noguchi , Yuichi Terashima , Hisamitsu Awaki

A new, complete sample of 14,584 broad-line AGNs at $z<0.35$ is presented, which are uncovered homogeneously from the complete database of galaxies and quasars observed spectroscopically in the Sloan Digital Sky Survey Seventh Data Release.…

Astrophysics of Galaxies · Physics 2019-07-31 He-Yang Liu , Wen-Juan Liu , Xiao-Bo Dong , Hongyan Zhou , Tinggui Wang , Honglin Lu , Weimin Yuan

We present Chandra ACIS-S X-ray imaging spectroscopy for five dual active galactic nucleus (AGN) candidates. Our targets were drawn from a sample of 1286 [O III]-selected AGN pairs systematically selected from the Sloan Digital Sky Survey…

Astrophysics of Galaxies · Physics 2019-09-25 Meicun Hou , Xin Liu , Hengxiao Guo , Zhiyuan Li , Yue Shen , Paul J. Green

Based on a comparison of the SRG/eROSITA catalog of X-ray active stars and the Gaia catalog, a sample of 502 peculiar objects was obtained for which Gaia, on one hand, detects statistically significant values of parallax or proper motion…

High Energy Astrophysical Phenomena · Physics 2023-01-20 I. M. Khamitov , I. F. Bikmaev , M. R. Gilfanov , R. A. Sunyaev , P. S. Medvedev , M. A. Gorbachev , E. N. Irtuganov

We first review some basic properties of the most important classes of active galactic nuclei (AGN), including quasars, blazars, Seyfert galaxies and radio galaxies. The most commonly accepted type of scheme designed to individually unify…

Astrophysics · Physics 2007-05-23 Paul J. Wiita

We investigate signs of Active Galactic Nucleus (AGN) in the luminous infrared galaxy NGC 3256 at both infrared and X-ray wavelengths. NGC 3256 has double, the Northern and Southern, nuclei (hereafter, N and S nuclei, respectively). We show…

Astrophysics of Galaxies · Physics 2015-06-03 Youichi Ohyama , Yuichi Terashima , Kazushi Sakamoto

The ``AGN Physics with the Sloan Digital Sky Survey'' conference was held at Princeton University in July 2003 to bring together groups working inside and outside of the SDSS collaboration at radio through X-ray wavelengths to discuss the…

Astrophysics · Physics 2009-11-10 Patrick B. Hall , Gordon T. Richards

Active galaxies hosting two accreting and merging super-massive black holes (SMBHs) -- dual Active Galactic Nuclei (AGN) -- are predicted by many current and popular models of black hole-galaxy co-evolution. We present here the results of a…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-18 D. J. Rosario , R. C. McGurk , C. E. Max , G. A. Shields , K. L. Smith , S. M. Ammons

The SWIFT gamma ray observatory's Burst Alert Telescope (BAT) has detected a sample of active galactic nuclei (AGN) based solely on their hard X-ray flux (14-195 keV). In this paper, we present for the first time {\it XMM-Newton} X-ray…

Astrophysics · Physics 2009-11-13 Lisa M. Winter , Richard F. Mushotzky , Jack Tueller , Craig Markwardt

We explore host galaxy properties and environment of a sample of Type 1 and 2 active galactic nuclei (AGN) taken from the COSMOS2015 catalog, within 0.3 $\leq z \leq$ 1.1 selected for their emission in X-rays, optical spectra and SED…

Astrophysics of Galaxies · Physics 2018-07-11 Carlos Guillermo Bornancini , Diego García Lambas

Balmer absorption is a rare phenomenon in active galactic nuclei (AGNs). So far, only seven Balmer-absorption AGNs have been reported in literature. We here report the identification of SDSS\,J112611.63+425246 as a new Balmer-absorption AGN…

Astrophysics of Galaxies · Physics 2015-06-23 J. Wang , D. W. Xu

Quasars and Active Galactic Nuclei (AGNs) are often obscured by dust and gas. It is normally assumed that the obscuration occurs in an oblate "obscuring torus", that begins at the radius at which the most refractive dust can remain solid.…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 Martin Elvis

IZw1 is the prototype narrow line quasar. This type of AGNs show a number of common peculiar characteristics whose physical origin is not yet well understood. Here, I review the results of a detailed study by Laor et al. (1997b) of the UV…

Astrophysics · Physics 2007-05-23 Ari Laor

We present a small sample of Chandra X-ray sources selected from the fields of ACIS observations which probe fluxes around the break in the hard band source counts. The targets of these fields include 9 nearby galaxy clusters, 1 distant…

Astrophysics · Physics 2009-09-17 P. Gandhi , C. S. Crawford , A. C. Fabian , R. M. Johnstone

Active galactic nuclei (AGNs) often exhibit broad-line regions (BLRs), populated by high-velocity clouds in Keplerian orbits around the central supermassive black hole (SMBH) at subparsec scales. During episodes of intense super-Eddington…

High Energy Astrophysical Phenomena · Physics 2025-08-27 Gustavo E. Romero , Pablo Sotomayor

Galaxies often contain large reservoirs of molecular gas which shape their evolution. This can be through cooling of the gas -- which leads to star formation, or accretion onto the central supermassive black hole -- which fuels AGN activity…

Astrophysics of Galaxies · Physics 2022-11-16 Tom Rose , B. R. McNamara , F. Combes , A. C. Edge , A. C. Fabian , M. Gaspari , H. Russell , P. Salomé , G. Tremblay , G. Ferland

Active Galactic Nuclei (AGNs) and their relativistic jets belong to the most promising class of ultra-high-energy cosmic ray (UHECR) accelerators. This compact review summarises basic experimental findings by recent instruments, and…

High Energy Astrophysical Phenomena · Physics 2022-11-23 Frank M. Rieger

We have examined a subset of 18 active galactic nuclei (AGNs) drawn from a sample of 81 galaxies that possess double-peaked narrow optical emission line spectra in the Sloan Digital Sky Survey, have two optical AGN emission components…

Narrow-line Seyfert 1 (NLSy1) galaxies are an enigmatic class of active galactic nuclei (AGN) that exhibit peculiar multiwavelength properties across the electromagnetic spectrum. For example, these sources have allowed us to explore the…

Astrophysics of Galaxies · Physics 2023-11-27 Vaidehi S. Paliya , C. S. Stalin , Alberto Dominguez , D. J. Saikia

We present results on over 100 high-redshift quasars found in the Sloan Digital Sky Survey (SDSS), using automated selection algorithms applied to SDSS imaging data and with spectroscopic confirmation obtained during routine spectroscopic…

‹ Prev 1 8 9 10 Next ›