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Measuring the redshift of active galactic nuclei (AGNs) requires the use of time-consuming and expensive spectroscopic analysis. However, obtaining redshift measurements of AGNs is crucial as it can enable AGN population studies, provide…

Active Galactic Nuclei (AGN) host powerful jets containing high-energy electrons and protons. The astrophysical environment where AGNs and their jets are found is characterized by large concentrations of both dark matter (DM) and…

High Energy Astrophysical Phenomena · Physics 2013-04-10 Stefano Profumo , Lorenzo Ubaldi , Mikhail Gorchtein

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

We present ground-based high-spatial resolution mid-infrared (MIR) observations of 20 nearby low-luminosity AGN (LLAGN) with VLT/VISIR and the preliminary analysis of a new sample of 10 low-luminosity Seyferts observed with Gemini/Michelle.…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 D. Asmus , S. F. Hönig , P. Gandhi , A. Smette , W. J. Duschl

We present an X-ray analysis of fourteen nearby (z < 0.044) AGN in low mass galaxies (M_* <= 5*10^9 Msun) selected based on their optical variability (Baldassare et al. 2020). Comparing and contrasting different AGN selection techniques in…

Astrophysics of Galaxies · Physics 2023-08-09 Alexander Messick , Vivienne Baldassare , Marla Geha , Jenny Greene

We explore the multiwavelength properties of AGN host galaxies for different classes of radio-selected AGN out to z$\lesssim$6 via a multiwavelength analysis of about 7700 radio sources in the COSMOS field. The sources were selected with…

The third Fermi-LAT catalog (3FGL) presented the data of the first four years of observations from the Fermi Gamma-ray Space Telescope mission. There are 3034 sources, 1010 of which still remain unidentified. Identifying and classifying…

We detect and study the properties of faint radio AGN in Luminous Red Galaxies (LRGs). The LRG sample comprises 760,000 objects from a catalog of LRG photometric redshifts constructed from the Sloan Digital Sky Survey (SDSS) imaging data,…

Astrophysics of Galaxies · Physics 2015-05-13 J. A. Hodge , G. R. Zeimann , R. H. Becker , R. L. White

3C 216 is an extragalactic radio source classified as a compact steep spectrum (CSS) object, associated with the source 4FGL J0910.0+4257 detected by the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope. The source…

High Energy Astrophysical Phenomena · Physics 2025-06-11 Federica Giacchino , Giovanni La Mura , Stefano Ciprini , Dario Gasparrini , Marcello Giroletti , Marco Laurenti

Various lines of evidence suggest that the cores of a large portion of early-type galaxies (ETGs) are virtually evacuated of warm ionised gas. This implies that the Lyman-continuum (LyC) radiation produced by an assumed active galactic…

Astrophysics of Galaxies · Physics 2016-10-12 Leandro S. M. Cardoso , Jean Michel Gomes , Polychronis Papaderos

We have completed a spectroscopic survey of X-ray point sources in eight low-redshift clusters of galaxies (0.05<z<0.31) and have identified 40 cluster members with broad-band (0.3-8 keV) X-ray luminosities between L_X = 8x10^{40} and…

Astrophysics · Physics 2009-11-11 Paul Martini , Daniel D. Kelson , Eunhyeuk Kim , John S. Mulchaey , Alex A. Athey

We present a census of local active galactic nuclei (AGN) at a redshift of $z\leq0.025$ selected using the high-ionization [Ne v] $\lambda14.32\,\mu$m emission line from the Infrared Database of Extragalactic Observables from Spitzer…

Astrophysics of Galaxies · Physics 2026-03-16 S. Yassir , A. Annuar

Recent James Webb Space Telescope (JWST) observations have revealed a population of compact extragalactic objects at $z\gtrsim4$ with red near-infrared colors, which have been dubbed as ``Little Red Dots" (LRDs). The…

Astrophysics of Galaxies · Physics 2024-09-16 Minghao Yue , Anna-Christina Eilers , Tonima Tasnim Ananna , Christos Panagiotou , Erin Kara , Takamitsu Miyaji

(abridged)The majority of Active Galactic Nuclei (AGN) suffer from significant obscuration by surrounding dust and gas. X-ray surveys in the 2-10 keV band will miss the most heavily-obscured AGN in which the absorbing column density exceeds…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Stephanie M. LaMassa , Timothy M. Heckman , Andrew A. Ptak , Ann Hornschemeier , Lucimara Martins , Paule Sonnentrucker , Christy Tremonti

We present a study of the stellar population in Low Luminosity AGN (LLAGN). Our goal is to search for spectroscopic signatures of young and intermediate age stars, and to investigate their relationship with the ionization mechanism in…

We present a sub-arcsec resolution radio imaging survey of a sample of 76 low-luminosity active galactic nuclei (LLAGN) that were previously not detected with the Very Large Array at 15 GHz. Compact, parsec-scale radio emission has been…

High Energy Astrophysical Phenomena · Physics 2018-09-12 Payaswini Saikia , Elmar Körding , Deanne L. Coppejans , Heino Falcke , David Williams , Ranieri D. Baldi , Ian Mchardy , Rob Beswick

Obtaining a census of active galactic nuclei (AGN) activity across cosmic time is critical to our understanding of galaxy evolution and formation. Many AGN classification techniques are compromised by dust obscuration. However, very long…

Astrophysics of Galaxies · Physics 2021-05-12 J. F. Radcliffe , P. D. Barthel , A. P. Thomson , M. A. Garrett , R. J. Beswick , T. W. B. Muxlow

The main fuelling processes for Active Galactic Nuclei (AGN) are currently unknown. Previous work showed that galaxies with a large kinematic misalignment between their stellar and gas reservoirs have a higher AGN fraction than galaxies…

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

Radio-quiet Seyfert galaxies have been detected in GeV gamma-rays by the $Fermi$ Large Area Telescope (LAT), but the origin of much of this emission is unclear. We consider the nearby example, the Seyfert galaxy GRS 1734-292, which exhibits…

High Energy Astrophysical Phenomena · Physics 2025-02-12 Nobuyuki Sakai , Tomoya Yamada , Yoshiyuki Inoue , Ellis R. Owen , Tomonari Michiyama , Ryota Tomaru , Yasushi Fukazawa