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A wide-frequency radio study of Active Galactic Nuclei (AGN) is crucial to evaluate the intervening radiative mechanisms responsible for the observed emission and relate them with the underlying accretion physics. We present wide frequency…

We constructed a sample of 23,344 radio-loud active galactic nuclei (RLAGN) from the catalogue derived from the LOFAR Two-Metre Sky Survey (LoTSS) survey of the HETDEX Spring field. Although separating AGN from star-forming galaxies remains…

Low-luminosity AGNs are perceived to be radio loud and devoid of a ``big blue bump'', indicating a transition from a radiatively efficient, geometrically thin, accretion disc in high-luminosity AGNs, to a geometrically thick, radiatively…

Astrophysics · Physics 2008-11-26 Dan Maoz

They are weak, they are small, and they are often overlooked, but they are numerous and an ubiquitous sign of accreting black holes: compact radio cores and jets in low-power AGN. Here I summarize our work concerning these radio cores and…

Astrophysics · Physics 2007-05-23 Heino Falcke

This paper reviews our current understanding of low-luminosity AGNs (LLAGNs) in the context of the advection-dominated accretion flow. The best investigated source, the supermassive black hole in our galactic center, Sgr A*, is emphasized…

Astrophysics · Physics 2007-05-23 Feng Yuan

As a class, LINERs and Low-Luminosity AGN tend to show little or no significant short-term variability (i.e., with time-scales less than a day). This is a marked break for the trend of increased variability in Seyfert 1 galaxies with…

Astrophysics · Physics 2009-10-30 A. Ptak , T. Yaqoob , R. Mushotzky , P. Serlemitsos , R. Griffiths

The majority of the activity around nearby (z ~ 0) supermassive black holes is found in low-luminosity active galactic nuclei (LLAGN), the most of them being classified as low ionization nuclear emission regions. Although these sources are…

High Energy Astrophysical Phenomena · Physics 2020-01-22 Raniere de Menezes , Rodrigo Nemmen , Justin D. Finke , Ivan Almeida , Bindu Rani

We explore an accretion model for low luminosity AGN (LLAGN) that attributes the low radiative output to a low mass accretion rate rather than a low radiative efficiency. In this model, electrons are assumed to drain energy from the ions as…

Astrophysics · Physics 2009-06-23 Erin J. D. Jolley , Zdenka Kuncic

The results of Chandra snapshot observations of 11 LINERs (Low-Ionization Nuclear Emission-line Regions), three low-luminosity Seyfert galaxies, and one HII-LINER transition object are presented. Our sample consists of all the objects with…

Astrophysics · Physics 2010-04-06 Yuichi Terashima , Andrew S. Wilson

I give a brief review of the observational properties of low-luminosity AGNs (LLAGNs). I outline some unresolved issues in the study of LLAGNs, emphasizing the uncertainties in the role of the truncated thin accretion disk, the dusty…

High Energy Astrophysical Phenomena · Physics 2013-02-05 Rodrigo Nemmen

We present the results of the analysis of a sample of 17 low-luminosity (L_x < 1e42 erg/s), radio loud AGNs in massive galaxies. The sample is extracted from the SDSS database and it spans uniformly a wide range in optical [OIII] emission…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 F. de Gasperin , A. Merloni , P. Sell , P. Best , S. Heinz , G. Kauffmann

Most active supermassive black holes (SMBH) in present-day galaxies are underfed and consist of low-luminosity active galactic nuclei (LLAGN). They have multiwavelength broadband spectral energy distributions (SED) dominated by non-thermal…

Astrophysics of Galaxies · Physics 2021-02-12 Ivan Almeida , Roberta Duarte , Rodrigo Nemmen

Recent studies of the cosmic X-ray background (XRB) have suggested the possible existence of a population of relatively faint sources with hard X-ray spectra; however, the emission mechanism remains unclear. If the hard X-ray emission is…

Astrophysics · Physics 2007-05-23 Insu Yi , Stephen P. Boughn

We investigate the X-ray origin in FR Is using the radio, submillimetre, optical, and {\em Chandra} X-ray data of a small sample consisting of eight FR I sources. These sources are very dim, with X-ray luminosities $L_{\rm X}/L_{\rm Edd}…

Astrophysics · Physics 2009-11-13 Qingwen Wu , Feng Yuan , Xinwu Cao

(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

Jets are ubiquitous in accreting black holes. Often ignored, they may be a major contributor to the emitted spectral energy distribution for sub-Eddington black holes. For example, recent observations of radio-to-X-ray correlations and…

The broadband spectral energy distribution (SED) of Active Galactic Nuclei (AGN) is investigated for a well-selected sample composed of $23$ Seyfert 1 galaxies observed simultaneously in the optical/UV and X-ray bands with the Neil Gehrels…

High Energy Astrophysical Phenomena · Physics 2019-06-12 Huaqing Cheng , Weimin Yuan , He-Yang Liu , A. A. Breeveld , Chichuan Jin , Bifang Liu

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

One of the most important features in active galactic nuclei (AGN) is the variability of their emission. Variability has been discovered at X-ray, UV, and radio frequencies on time scales from hours to years. Among the AGN family and…

High Energy Astrophysical Phenomena · Physics 2015-06-15 L. Hernández-García , O. González-Martín , I. Márquez , J. Masegosa

We present high-resolution mid-infrared (MIR) imaging, nuclear spectral energy distributions (SEDs) and archival Spitzer spectra for 22 low-luminosity active galactic nuclei (LLAGN; Lbol \lesssim 10^42 erg/sec). Infrared (IR) observations…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 R. E. Mason , E. Lopez-Rodriguez , C. Packham , A. Alonso-Herrero , N. A. Levenson , J. Radomski , C. Ramos Almeida , L. Colina , M. Elitzur , I. Aretxaga , P. F. Roche , N. Oi