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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 a spectroscopic sample of 23 broad-line AGNs (BLAGNs) at $3\lesssim z\lesssim 6$ selected using F322W2+F444W NIRCam/WFSS grism spectroscopy of the central 100 ${\rm arcmin^2}$ area of the NEXUS survey. Among these BLAGNs, 15 are…

Astrophysics of Galaxies · Physics 2025-05-28 Ming-Yang Zhuang , Junyao Li , Yue Shen , Xiaojing Lin , Alice E. Shapley , Feige Wang , Qiaoya Wu , Qian Yang

We used data from the QUEST-La Silla Active Galactic Nuclei (AGN) variability survey to construct light curves for 208,583 sources over $\sim 70$ deg$^2$, with a a limiting magnitude $r \sim 21$. Each light curve has at least 40 epochs and…

Astrophysics of Galaxies · Physics 2019-05-29 P. Sánchez-Sáez , P. Lira , R. Cartier , N. Miranda , L. C. Ho , P. Arévalo , F. E. Bauer , P. Coppi , C. Yovaniniz

We investigate the properties of active galactic nuclei (AGNs) in the brightest submillimeter galaxies (SMGs) in the COSMOS field. We utilize the bright sample of ALMA/SCUBA-2 COSMOS Survey (AS2COSMOS), which consists of 260 SMGs with…

We present the results of a program to identify so far unknown active nuclei (AGN) in galaxies. Candidate galactic nuclei have been selected for optical spectroscopy from a cross-correlation of the ROSAT all sky survey (RASS) bright source…

Astrophysics · Physics 2007-05-23 K. Bischoff , W. Pietsch , T. Boller , S. Döbereiner , W. Kollatschny , H. -U. Zimmermann

The second catalog of active galactic nuclei (AGNs) detected by the Fermi Large Area Telescope (LAT) in two years of scientific operation is presented. The Second LAT AGN Catalog (2LAC) includes 1017 gamma-ray sources located at high…

High Energy Astrophysical Phenomena · Physics 2015-05-30 LAT Collaboration

We present the third catalog release of the wide-area (31.3 deg$^2$) Stripe 82 X-ray survey. This catalog combines previously published X-ray source properties with multiwavelength counterparts and photometric redshifts, presents 343 new…

This work discusses the broadband X-ray spectral analysis of 11 candidate heavily-obscured active galactic nuclei (AGN) selected based on their infrared and X-ray properties by a recently published machine learning algorithm. This paper is…

(abridged) We identify a numerically significant population of heavily obscured AGNs at z~0.5-1 in the Chandra Deep Field-South (CDF-S) and Extended Chandra Deep Field-South by selecting 242 X-ray undetected objects with infrared-based star…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 B. Luo , W. N. Brandt , Y. Q. Xue , D. M. Alexander , M. Brusa , F. E. Bauer , A. Comastri , A. C. Fabian , R. Gilli , B. D. Lehmer , D. A. Rafferty , D. P. Schneider , C. Vignali

We aim to study the effect of environment on the presence and fuelling of Active Galactic Nuclei (AGN) in massive galaxy clusters. We explore the use of different AGN detection techniques with the goal of selecting AGN across a broad range…

Astrophysics of Galaxies · Physics 2015-06-05 Alison J. Klesman , Vicki L. Sarajedini

We study the size of BLRs of low luminosity Active Galactic Nuclei, also called 'dwarf AGN', defined as having ($L_{H\alpha}\le10^{41}{\rm erg\cdot s^{-1}}$)). We more than double the sample size analyzed previously (Wang & Zhang 2003,…

Astrophysics · Physics 2018-08-08 Zhang Xue-Guang , Deborah Dultzin-Hacyan , Wang Ting-Gui

We present NIR spectroscopy using MMT/MMIRS for a sample of twenty-nine massive galaxies ($\mathrm{log\ M_* / M_{\odot} \gtrsim10}$) at $\mathrm{z\sim0.7}$ with optical spectroscopy from the LEGA-C survey. Having both optical and NIR…

We report the discovery of 13 broad-line AGNs at $z = 5 - 8$ from the first 10% data of the JWST Cycle 3 Treasury Program COSMOS-3D. These AGNs are identified by their broad H$\alpha$ or H$\beta$ emission lines through the NIRCam grism…

We compiled a sample of 95 AGNs serendipitously detected in the 3-20 keV band at Galactic latitude |b|>10 during the RXTE slew survey (XSS, Revnivtsev et al.), and utilize it to study the statistical properties of the local population of…

Astrophysics · Physics 2009-11-10 S. Sazonov , M. Revnivtsev

We present a detailed study of the optical spectroscopic properties of 12 active galactic nuclei (AGNs) with candidate low-mass black holes (BHs) selected by Kamizasa et al. through rapid X-ray variability. The high-quality, echellette…

Astrophysics of Galaxies · Physics 2016-04-20 Luis Ho , Minjin Kim

Variability studies hold information on otherwise unresolvable regions in Active Galactic Nuclei (AGN). Population studies of large samples likewise have been very productive for our understanding of AGN. These two themes are coming…

High Energy Astrophysical Phenomena · Physics 2016-05-31 Andy Lawrence

We present the results of our search for highly variable active galactic nuclei (AGNs) the X-ray flux from which changed by more than an order of magnitude during the SRG/eROSITA all-sky survey. Using the eROSITA data obtained in the period…

High Energy Astrophysical Phenomena · Physics 2023-09-21 Pavel Medvedev , Marat Gilfanov , Sergey Sazonov , Rashid Sunyaev , Georgii Khorunzhev

A new sample of 204 low-mass black holes (LMBHs) in active galactic nuclei (AGNs) is presented with black hole masses in the range of (1-20) * 10^5 M_sun. The AGNs are selected from a systematic search among galaxies in the Seventh Data…

Astrophysics of Galaxies · Physics 2018-05-04 He-Yang Liu , Weimin Yuan , Xiao-Bo Dong , Hongyan Zhou , Wen-Juan Liu

In order to answer some of the major open questions in the fields of supermassive black hole (SMBH) and galaxy evolution, a complete census of SMBH growth, i.e., active galactic nuclei (AGN), is required. Thanks to deep all-sky surveys,…