中文
相关论文

相关论文: Seyfert galaxies: Nuclear Radio Structure and Unif…

200 篇论文

A radio study of a carefully selected sample of 20 Seyfert galaxies that are matched in orientation-independent parameters, which are measures of intrinsic active galactic nuclei (AGN) power and host galaxy properties is presented to test…

宇宙学与河外天体物理 · 物理学 2015-05-27 Dharam V. Lal , Prajval Shastri , Denise Gabuzda

We have obtained mas-scale resolution very long baseline interferometry (VLBI) images of a sample of Seyfert 1 and Seyfert 2 galaxies at 5 GHz (wavelength, $\lambda$ = 6 cm). The Seyferts of the two types were chosen to be matched in…

天体物理学 · 物理学 2009-11-10 Dharam Vir Lal , Prajval Shastri , Denise C. Gabuzda

Aims. We present low-frequency radio imaging and spectral properties of a well defined sample of Seyfert galaxies using GMRT 240/610 MHz dual frequency observations. Radio spectra of Seyfert galaxies over 240 MHz to 5.0 GHz are investigated…

宇宙学与河外天体物理 · 物理学 2013-04-23 Veeresh Singh , Prajval Shastri , Ishwara-Chandra C. H. , Ramana Athreya

We have observed a sample of 157 Seyfert galaxies with a 275 km baseline radio interferometer to search for compact, high brightness temperature radio emission from the active nucleus. We obtain the surprising result that compact radio…

天体物理学 · 物理学 2009-10-22 A. L. Roy , R. P. Norris , M. J. Kesteven , E. R. Troup , J. E. Reynolds

We present a series of statistical tests done to a sample of 29 Seyfert 1 and 59 Seyfert 2 galaxies selected from mostly isotropic properties, their far infrared fluxes and warm infrared colors. Such selection criteria provide a profound…

天体物理学 · 物理学 2009-11-06 H. R. Schmitt , R. R. J. Antonucci , J. S. Ulvestad , A. L. Kinney , C. J. Clarke , J. E. Pringle

Context: The unification scheme of Seyfert galaxies hypothesizes that Seyfert type 1s and type 2s are intrinsically similar and the observed differences between the two subtypes are solely due to the differing orientations of…

宇宙学与河外天体物理 · 物理学 2011-08-19 Veeresh Singh , Prajval Shastri , Guido Risaliti

We have carried out an analysis of the radio and optical properties of a statistical sample of 45 Seyfert galaxies from the Palomar spectroscopic survey of nearby galaxies. We find that the space density of bright galaxies (-22 mag <=…

天体物理学 · 物理学 2009-11-06 James S. Ulvestad , Luis C. Ho

We discuss the properties of compact nuclear radio components in Seyfert galaxies from the extended 12-micron AGN sample of Rush et al.(1993). Our main results can be summarised as follows. Type 1 and type 2 Seyferts produce compact radio…

天体物理学 · 物理学 2009-11-06 Andy Thean , Alan Pedlar , Marek J. Kukula , Stefi A. Baum , Christopher P. O'Dea

We present near-to-mid-infrared spectral energy distributions (SEDs) for 21 Seyfert galaxies, using subarcsecond resolution imaging data. Our aim is to compare the properties Seyfert 1 (Sy1) and Seyfert 2 (Sy2) tori using clumpy torus…

Observations at ultraviolet, optical and near-infrared wavelengths have shown the existence of recent star formation in the nuclear regions of Seyfert 2 (Sy2) galaxies that suggest a connection between the Starburst and the Seyfert…

天体物理学 · 物理学 2007-05-23 Rosa M. Gonzalez Delgado

Our understanding of the unification of jetted AGNs has advanced greatly as the size of extragalactic sources increased. In the present paper, based on the large sample of radio sources, we compiled 680 blazars (279 FSRQs and 401 BL Lacs)…

星系天体物理 · 物理学 2021-11-17 E. U. Iyida , I. O. Eya , F. C. Odo

We report the first results of a survey on 74 narrow-line Seyfert 1 galaxies (NLS1s) carried out in 2015 with the Karl G. Jansky Very Large Array (JVLA) at 5 GHz in A-configuration. So far, this is the largest survey aimed to image the…

Narrow-line Seyfert 1 (NLS1) galaxies are a type of active galactic nuclei (AGN) that were originally classified as sources with little to no radio emission. Although the class is rather unified from an optical perspective, their radio…

星系天体物理 · 物理学 2025-11-26 I. Varglund , E. Järvelä , M. J. Hardcastle , S. Varglund , A. Lähteenmäki

Parallel analysis of the large-scale morphology and local environment of matched active and control galaxy samples plays an important role in studies of the fueling of active galactic nuclei. We carry out a detailed morphological…

宇宙学与河外天体物理 · 物理学 2010-11-09 L. Slavcheva-Mihova , B. Mihov

Statistical analyses are invaluable methods used to understand intrinsic emission processes and the unification of extragalactic radio sources. In this paper, we collected radio, X-ray and {\gamma}-ray data of blazars from the Fermi-LAT and…

高能天体物理现象 · 物理学 2021-12-08 E. U. Iyida , I. O. Eya , F. C. Odo

Here we present the first results from the Siding Spring Southern Seyfert Spectroscopic Snapshot Survey (S7) which aims to investigate the physics of ~140 radio-detected southern active Galaxies with z<0.02 through Integral Field…

Aims: The unification scheme of Seyfert galaxies predicts that the observed differences between type 1 and type 2 Seyfert galaxies are solely due to the differing orientations of the toroidal-shaped obscuring material around AGN. The…

高能天体物理现象 · 物理学 2015-03-17 Veeresh Singh , Prajval Shastri , Guido Risaliti

The VLA has been used at 3.6 and 20 cm to image a sample of about 50 early-type Seyfert galaxies with recessional velocities less than 7,000 km/s and total visual magnitude less than 14.5. The nuclear radio structures of Seyfert 2.0's in…

天体物理学 · 物理学 2009-10-31 Neil M. Nagar , Andrew S. Wilson , John S. Mulchaey , Jack F. Gallimore

Aims.The main purpose of this study is to investigate aspects regarding the validity of the active galactic nucleus (AGN) unification paradigm (UP). In particular, we focus on the AGN host galaxies, which according to the UP should show no…

星系天体物理 · 物理学 2021-09-03 Anamaria Gkini , Manolis Plionis , Maria Chira , Elias Koulouridis

We studied the physical parameters of a sample comprising of all Spitzer/IRS public spectra of Seyfert galaxies in the mid-infrared (5.2-38$\mu$m range) under the active galactic nuclei (AGN) unified model. We compare the observed spectra…

‹ 上一页 1 2 3 10 下一页 ›