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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…

Astrophysics · Physics 2009-11-06 Andy Thean , Alan Pedlar , Marek J. Kukula , Stefi A. Baum , Christopher P. O'Dea

(abbreviated): This paper presents the results of a high resolution radio imaging survey of all known (96) low-luminosity active galactic nuclei (LLAGNs) at D<19Mpc. We find that almost half of all LINERs and low-luminosity Seyferts have…

Astrophysics · Physics 2009-11-07 N. M. Nagar , H. Falcke , A. S. Wilson , J. S. Ulvestad

Radio emission from the high- and super-Eddington accreting active galactic nuclei (AGNs) has various origins: a persistent jet, the magnetized corona and the wind-like outflows. It is now still unclear which is the leading mechanism…

High Energy Astrophysical Phenomena · Physics 2020-12-16 Xiaolong Yang , Su Yao , Jun Yang , Luis C. Ho , Tao An , Ran Wang , Willem A. Baan , Minfeng Gu , Xiang Liu , Xiaofeng Yang , Ravi Joshi

We have surveyed two large samples of nearby low-luminosity AGN with the VLA to search for flat-spectrum radio cores, similar to Sgr A* in the Galactic Center. Roughly one third of all galaxies are detected (roughly one half if HII…

Astrophysics · Physics 2015-06-24 Heino Falcke , Neil M. Nagar , Andrew S. Wilson , Luis C. Ho , Jim S. Ulvestad

We present polarization-sensitive images from the Karl G. Jansky Very Large Array (VLA) at 5 GHz of 11 radio-quiet PG quasars. Based on the radio morphology, spectral index and polarization properties from the VLA study, coupled with the…

Astrophysics of Galaxies · Physics 2024-02-21 Silpa S. , P. Kharb , Luis C. Ho , C. M. Harrison

We present here the results from dual-frequency phase-referenced VLBI observations of the Seyfert galaxy KISSR1494, which exhibits double peaked emission lines in its SDSS spectrum. We detect a single radio component at 1.6 GHz, but not at…

Astrophysics of Galaxies · Physics 2015-06-23 Preeti Kharb , Mousumi Das , Zsolt Paragi , Smitha Subramanian , Lakshmi Pradeep Chitta

We report a 0.2" resolution, 15 GHz survey of a sample of 48 low-luminosity active galactic nuclei with the Very Large Array. Compact radio emission has been detected in 57% (17 of 30) of LINERs and low-luminosity Seyferts, at least 15 of…

Astrophysics · Physics 2009-10-31 Neil M. Nagar , Heino Falcke , Andrew S. Wilson , Luis C. Ho

We have used the VLBA at 5 GHz to observe all galaxies with nuclear radio flux densities above 3.5 mJy found in a VLA survey at 15 GHz of a sample of nearby LINER galaxies. All galaxies were detected revealing high brightness temperature…

Astrophysics · Physics 2009-10-31 Heino Falcke , Neil M. Nagar , Andrew S. Wilson , James S. Ulvestad

We present polarization images from the Karl G. Jansky Very Large Array (VLA) and the Giant {Metrewave} Radio Telescope (GMRT) at 5.5, 10 GHz and 663 MHz of the changing-look (CL) AGN, NGC3516. A transverse gradient in the rotation measure…

Astrophysics of Galaxies · Physics 2025-06-16 Salmoli Ghosh , P. Kharb , E. Sajjanhar , A. Pasetto , B. Sebastian

We present the results of a multi-frequency, multi-scale radio polarimetric study with the Very Large Array (VLA) of the Seyfert 1 galaxy and BALQSO, Mrk 231. We detect complex total and polarized intensity features in the source. Overall,…

Astrophysics of Galaxies · Physics 2021-11-16 Silpa S. , P. Kharb , C. P. O' Dea , S. A. Baum , B. Sebastian , D. Mukherjee , C. M. Harrison

We investigate the radio emitting structures of radio-quiet active galactic nuclei with an emphasis on radio-quiet quasars to study their connection to Seyfert galaxies. We present and analyse high-sensitivity VLA radio continuum images of…

Astrophysics · Physics 2009-11-11 Christian Leipski , Heino Falcke , Nicola Bennert , Susanne Huettemeister , ;

We present 1-7 GHz high-resolution radio imaging (VLA and e-MERLIN) and spatially-resolved ionized gas kinematics for ten z<0.2 type~2 `obscured' quasars (log [L(AGN)/(erg/s)]>~45) with moderate radio luminosities (log…

The compact radio source Sgr A* is coincident with a 4 million solar mass black hole at the dynamical center of the Galaxy and is surrounded by dense orbiting ionized and molecular gas. We present high resolution radio continuum images of…

High Energy Astrophysical Phenomena · Physics 2015-06-11 F. Yusef-Zadeh , R. Arendt , H. Bushouse , W. Cotton , D. Haggard , M. W. Pound , D. A. Roberts , M. Royster , M. Wardle

The appearance of the jets and lobes of some radio galaxies makes it difficult to assign them to a known class of objects. This is often due to the activity of the central engine and/or interactions with the environment, as well as…

Astrophysics of Galaxies · Physics 2024-11-05 M. Weżgowiec , M. Jamrozy , K. T. Chyży , M. J. Hardcastle , A. Kuźmicz , G. Heald , T. W. Shimwell

A number of radio galaxies has been detected by Fermi/LAT in the gamma-ray domain. In some cases, like Cen A and M 87, these objects have been seen even in the TeV range by Cherenkov telescopes. Whereas the gamma-ray emission is likely to…

High Energy Astrophysical Phenomena · Physics 2013-02-20 V. Beckmann , S. de Jong , F. Mattana , D. Saez , S. Soldi

We study a complete and distance-limited sample of 25 LINERs, 21 of which have been imaged with the Hubble Space Telescope to study their physical properties and to compare their radio and optical properties with those of other samples of…

Astrophysics · Physics 2015-06-24 F. D. Macchetto , M. Chiaberge

In inhomogeneous optically thick synchrotron sources a substantial part of the electron population at low energies can be hidden by self-absorption and overpowered by high energy electrons in optically thin emission. These invisible…

Astrophysics · Physics 2009-11-07 Thomas Beckert , Heino Falcke

We present the detection of compact radio structures of fourteen radio-loud narrow line Seyfert 1 (NLS1) galaxies from Very Long Baseline Array observations at 5 GHz, which were performed in 2013. While 50\% of the sources of our sample…

Astrophysics of Galaxies · Physics 2015-10-14 Minfeng Gu , Yongjun Chen , S. Komossa , Weimin Yuan , Zhi-Qiang Shen , Kiyoaki Wajima , Hongyan Zhou , J. A. Zensus

We have conducted a multiwavelength survey of 42 radio loud narrow-1ine Seyfert 1 galaxies (RLNLS1s), selected by searching among all the known sources of this type and omitting those with steep radio spectra. We analyse data from radio…

The dichotomy between radio-loud (RL) and radio-quiet (RQ) active galactic nuclei (AGN) is thought to be intrinsically related to radio jet production. This difference may be explained by the presence of a strong magnetic field (B-field)…