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X-ray surveys have revealed a new class of active galactic nuclei (AGN) with a very low observed fraction of scattered soft X-rays, f_scat < 0.5%. Based on X-ray modeling these "X-ray new-type", or low observed X-ray scattering…

Astrophysics of Galaxies · Physics 2015-06-17 S. F. Hoenig , P. Gandhi , D. Asmus , R. F. Mushotzky , R. Antonucci , Y. Ueda , K. Ichikawa

We characterize the incidence of active galactic nuclei (AGNs) is 0.3 < z < 1 star-forming galaxies by applying multi-wavelength AGN diagnostics (X-ray, optical, mid-infrared, radio) to a sample of galaxies selected at 70-micron from the…

(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 have assembled a sample of 64 late-type spiral galaxies (T types 6.0-9.0, corresponding to Hubble types Scd-Sm) with archival Chandra data. At a signal-to-noise (S/N) threshold of 3, we find 12 objects with X-ray point-source detections…

Astrophysics · Physics 2008-09-10 Louis-Benoit Desroches , Luis Ho

Kpc-scale dual and offset Active Galactic Nuclei (AGNs) are signposts of accreting supermassive black holes (SMBHs) triggered during late-stage galaxy mergers, offering crucial insights into the coevolution of SMBHs and galaxies. However,…

Astrophysics of Galaxies · Physics 2024-05-27 Junyao Li , Ming-Yang Zhuang , Yue Shen , Marta Volonteri , Nianyi Chen , Tiziana Di Matteo

The $\gamma$-ray emission from active galactic nuclei (AGN), including both beamed blazars and misaligned-AGN, dominates the extragalactic $\gamma$-ray point-source population count and flux. While multi-wavelength studies have detected an…

High Energy Astrophysical Phenomena · Physics 2025-09-26 Milena Crnogorčević , Tim Linden , Annika H. G. Peter

We analyze observations obtained with the Chandra X-ray Observatory of bright Compton thick active galactic nuclei (AGNs), those with column densities in excess of 1.5 x 10^{24} cm^{-2} along the lines of sight. We therefore view the…

Astrophysics · Physics 2011-07-21 N. A. Levenson , T. M. Heckman , J. H. Krolik , K. A. Weaver , P. T. Zycki

Type 2 active galactic nuclei (AGN) show signatures of accretion onto a supermassive black hole through strong, high-ionization, narrow emission lines extended on scales of 100s to 1000s of parsecs, but they lack the broad emission lines…

High Energy Astrophysical Phenomena · Physics 2022-09-21 M. Lynne Saade , Murray Brightman , Daniel Stern , Matthew A. Malkan , Javier A. Garcia

The Swift Burst Alert Telescope (BAT) survey of Active Galactic Nuclei (AGN) is providing an unprecedented view of local AGNs (<z> = 0.03) and their host galaxy properties. In this paper, we present an analysis of the optical spectra of a…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 Lisa M. Winter , Karen T. Lewis , Michael Koss , Sylvain Veilleux , Brian Keeney , Richard F. Mushotzky

Heavily obscured Active Galactic Nuclei (AGN), especially Compton-thick sources with line-of-sight column density ($N_{\rm H,los}$) $>$ 10$^{24}$ cm$^{-2}$, are critical to understanding supermassive black hole (SMBH) growth and the origin…

We explore the characteristics of actively accreting MBHs within dwarf galaxies in the \textsc{Romulus25} cosmological hydrodynamic simulation. We examine the MBH occupation fraction, x-ray active fractions, and AGN scaling relations within…

Astrophysics of Galaxies · Physics 2022-09-07 Ray S. Sharma , Alyson M. Brooks , Michael Tremmel , Jillian Bellovary , Angelo Ricarte , Thomas R. Quinn

We present a detailed and self-consistent modeling of the cosmic X-ray background (XRB) based on the most up-to-date X-ray luminosity functions (XLF) and evolution of Active Galactic Nuclei (AGN). The large body of observational results…

Astrophysics · Physics 2009-11-11 Roberto Gilli , Andrea Comastri , Guenther Hasinger

X-ray surveys provide the most efficient means for the detection of Active Galactic Nuclei (AGN). However, they face difficulties in detecting the most heavily obscured Compton-thick AGN. The BAT detector on board the Gehrels/Swift mission,…

Astrophysics of Galaxies · Physics 2024-12-25 A. Akylas , I. Georgantopoulos , P. Gandhi , P. Boorman , C. L. Greenwell

The cosmic X-ray background (CXB) is dominated by the obscured and unobscured coronal light of active galactic nuclei (AGN). At energies below 10 keV, the CXB can be well explained by models taking into account the known AGN and the…

High Energy Astrophysical Phenomena · Physics 2025-02-03 Isaiah S. Cox , Núria Torres-Albà , Stefano Marchesi , Peter Boorman , Xiurui Zhao , Ross Silver , Marco Ajello , Indrani Pal

This paper explores the role of small-scale environment ($<1$ Mpc) in modulating accretion events onto supermassive black holes by studying the incidence of Active Galactic Nuclei (AGN) in massive clusters of galaxies. A flexible,…

Binary active galactic nuclei (AGNs) provide clues to how gas-rich mergers trigger and fuel AGNs and how supermassive black hole (SMBH) pairs evolve in a gas-rich environment. While significant effort has been invested in their…

Astrophysics of Galaxies · Physics 2016-05-24 Jinyi Shangguan , Xin Liu , Luis C. Ho , Yue Shen , Chien Y. Peng , Jenny E. Greene , Michael A. Strauss

Modern cosmological simulations rely heavily on feedback from active galactic nuclei (AGN) in order to stave off overcooling in massive galaxies and galaxy groups and clusters. An important independent test is whether or not the simulations…

In this paper we present data from 72 low redshift, hard X-ray selected AGN taken from the {\it Swift}-BAT 58 month catalogue. We utilise spectral energy distribution fitting to the optical to IR photometry in order to estimate host galaxy…

Astrophysics of Galaxies · Physics 2020-08-13 Thomas M. Jackson , D. J. Rosario , D. M. Alexander , J. Scholtz , Stuart McAlpine , R. G. Bower

We investigate the role of host galaxy classification and black hole mass in a heterogeneous sample of 276 mostly nearby (z<0.1) X-ray and IR selected AGN. Around 90% of Seyfert 1 AGN in bulge-dominated host galaxies (without disk…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 Barry McKernan , K. E. Saavik Ford , Chris Reynolds

We investigated AGN activity in low-mass galaxies, an important regime that can shed light onto BH formation and evolution, and their interaction with their host galaxies. We identified 336 AGN candidates from a parent sample of $\sim…