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Active Galactic Nuclei (AGN) may emit highly collimated and intense jets of relativistic electrons which upscatter ambient photons. These electrons can also scatter off the cold dark matter halo of the galaxy to produce high energy photons…

Astrophysics · Physics 2010-11-30 Elliott D. Bloom , James D. Wells

Using the CIGALE software, we present the preliminary results of a multiwavelength analysis of eighteen low-redshift isolated galaxies with active nuclei (isolated AGNs). This sample was formed by cross-matching the 2MIG isolated AGNs…

Astrophysics of Galaxies · Physics 2025-11-26 O. Kompaniiets

We use Chandra data to study the incidence and properties of Active Galactic Nuclei (AGN) in 16 intermediate redshift ($0.5 < z < 1.1$) X-ray-selected galaxy groups in the Chandra Deep Field-South. We measure an AGN fraction of $f(L_{X,H} >…

We study a combined sample of 264 star-forming, 51 composite, and 73 active galaxies using optical spectra from SDSS and mid-infrared (mid-IR) spectra from the Spitzer Infrared Spectrograph. We examine optical and mid-IR spectroscopic…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 Stephanie M. LaMassa , T. M. Heckman , A. Ptak , D. Schiminovich , M. O'Dowd , B. Bertincourt

We assemble a sample of 733 dwarf galaxies ($M_{\ast} \le 10^{9.5} \text{M}_\odot$) with signatures of active galactic nuclei (AGN) and explore the intersection between different AGN selection techniques. Objects in our database are…

Astrophysics of Galaxies · Physics 2024-05-31 Erik J. Wasleske , Vivienne F. Baldassare

In the era of massive photometric surveys, we explore several approaches to estimate the masses of supermassive black holes (SMBHs) in active galactic nuclei (AGN) from optical ground-based imaging, in each case comparing to the independent…

Astrophysics of Galaxies · Physics 2024-09-02 Sarah Casura , Dragana Ilić , Jonathan Targaczewski , Nemanja Rakić , Jochen Liske

We study the morphology of the central region of a sample of Active Galactic Nuclei (AGN) and a ``control'' sample of normal galaxies using archival observations of the WFPC2 instrument onboard the Hubble Space Telescope (HST). We use the…

Astrophysics · Physics 2009-11-07 E. M. Xilouris , I. E. Papadakis

The aim of this paper is to revisit critically the current census of AGN as derived from optical spectroscopy. We considered the spectra of nearby (z<0.1) galaxies from the Sloan Digital Sky Survey (SDSS). The equivalent width (EW)…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 Alessandro Capetti

A majority of the active galactic nuclei (AGN) in the local Universe are classified as low-luminosity AGN (LLAGN), having bolometric luminosities $\lesssim 10^{42} \ \mathrm{erg \ s^{-1}}$. Although high-energy gamma-ray emission is…

High Energy Astrophysical Phenomena · Physics 2026-04-08 Chris Karwin , Nikita Khatiya , Margot Boughelilba , Xiurui Zhao , Anita Reimer , Marco Ajello

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

We quantify the presence of Active Galactic nuclei (AGN) in a mass-complete (M_* >5e10 M_sun) sample of 123 star-forming and quiescent galaxies at 1.5 < z < 2.5, using X-ray data from the 4 Ms Chandra Deep Field-South (CDF-S) survey.…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 Karen Pardos Olsen , Jesper Rasmussen , Sune Toft , Andrew W. Zirm

We have employed a reliable technique of classification of Active Galactic Nuclei (AGN) based on the fit of well-sampled spectral energy distributions (SEDs) with a complete set of AGN and starburst galaxy templates. We have compiled…

Extragalactic radio continuum surveys play an increasingly more important role in galaxy evolution and cosmology studies. While radio galaxies and radio quasars dominate at the bright end, star-forming galaxies (SFGs) and radio-quiet Active…

We present a new method to predict the line-of-sight column density (NH) values of active galactic nuclei (AGN) based on mid-infrared (MIR), soft, and hard X-ray data. We developed a multiple linear regression machine learning algorithm…

Astrophysics of Galaxies · Physics 2023-07-05 Ross Silver , Núria Torres-Alba , Xiurui Zhao , Stefano Marchesi , Andrealuna Pizzetti , Isaiah Cox , Marco Ajello

We performed near-diffraction-limited (~0.4 FWHM) N-band imaging of one of the nearest Active Galactic Nucleus (AGN) in M51 with 8.2m Subaru telescope to study the nuclear structure and spectral energy distribution (SED) at 8-13 um. We…

Astrophysics of Galaxies · Physics 2017-02-01 Youichi Ohyama , Satoki Matsushita , Nagisa Oi , Ai-Lei Sun

We report on Chandra X-ray observations of four candidate low-mass black hole (<10^6Msun) active galactic nuclei (AGNs) that have the estimated Eddington ratios among the lowest (~10^(-2)) found for this class. The aims are to validate the…

Astrophysics of Galaxies · Physics 2015-06-18 W. Yuan , H. Zhou , L. Dou , X. -B. Dong , X. Fan , T. -G. Wang

Spectral energy distributions (SEDs) of the central few tens of parsec region of some of the nearest, most well studied, active galactic nuclei (AGN) are presented. These genuine AGN-core SEDs, mostly from Seyfert galaxies, are…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 M. A. Prieto , J. Reunanen , K. R. W. Tristram , N. Neumayer , J. A. Fernandez-Ontiveros , M. Orienti , K. Meisenheimer

Context: Finding Active Galactic Nuclei (AGN) behind the Magellanic Clouds (MCs) is difficult because of the high stellar density in these fields. Although the first AGN behind the Small Magellanic Cloud (SMC) were reported in the 1980s, it…

High Energy Astrophysical Phenomena · Physics 2019-01-30 C. Maitra , F. Haberl , V. D. Ivanov , Maria-Rosa L. Cioni , Jacco Th. van Loon

Searching for active galactic nuclei (AGN) in dwarf galaxies is important for our understanding of the seed black holes that formed in the early Universe. Here, we test infrared selection methods for AGN activity at low galaxy masses. Our…

Astrophysics of Galaxies · Physics 2016-12-07 Kevin N. Hainline , Amy E. Reines , Jenny E. Greene , Daniel Stern

We present spectroscopic observations of 27 active galactic nuclei (AGN) with some of the lowest black hole (BH) masses known. We use the high spectral resolution and small aperture of our Keck data, taken with the Echellette Spectrograph…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 Randi R. Ludwig , Jenny E. Greene , Aaron J. Barth , Luis C. Ho