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We present the discovery of an active galactic nucleus (AGN) that is turning off and then on again in the z=0.06 galaxy SDSS J1354+1327. This episodic nuclear activity is the result of discrete accretion events, which could have been…

A recent ALMA study of the Seyfert 2 Active Galactic Nucleus (AGN) NGC 2110 by Rosario et al. (2019) has reported a remarkable lack of CO 2-1 emission from the circumnuclear region, where optical lines and H2 emission are observed, leading…

Astrophysics of Galaxies · Physics 2019-05-15 G. Fabbiano , A. Paggi , M. Elvis

We present {\it Gemini} longslit optical spectroscopy and VLA radio observations of the nuclear region of NGC 4178, a late-type bulgeless disk galaxy recently confirmed to host an AGN through infrared and X-ray observations. Our…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 Nathan Secrest , Shobita Satyapal , Sean Moran , Teddy Cheung , Marcello Giroletti , Mario Gliozzi , Marcel Bergmann , Anil Seth

We present a multi-wavelength study of the active nucleus and the off-nuclear X-ray sources in the nearby spiral galaxy, NGC 1365 using three simultaneous UV/X-ray observations by AstroSat over a two months period and archival IR…

High Energy Astrophysical Phenomena · Physics 2023-02-08 Subhashree Swain , Gulab Chand Dewangan , P. Shalima , Prakash Tripathi , K . V. P. Latha

We present an analysis of the optical nuclear spectra from the active galactic nuclei (AGN) in a sample of giant low surface brightness (GLSB) galaxies. GLSB galaxies are extreme late type spirals that are large, isolated and poorly evolved…

Astrophysics of Galaxies · Physics 2017-08-23 Smitha Subramanian. , Ramya. S. , Mousumi Das. , Koshy George. , T. Sivarani , T. P. Prabhu

The aim of this study is to constrain the dynamics, structure and feeding of the compact nucleous of NGC4418, and to reveal the nature of the main hidden power source: starburst or AGN. We obtained high spatial resolution observations of…

Astrophysics of Galaxies · Physics 2015-06-16 F. Costagliola , S. Aalto , K. Sakamoto , S. Martín , R. Beswick , S. Muller , H. -R. Klöckner

We present a structural study of 182 obscured Active Galactic Nuclei (AGNs) at z<=1.5, selected in the COSMOS field from their extreme infrared to X-ray luminosity ratio and their negligible emission at optical wavelengths. We fit optical…

The colossal power output of active galactic nuclei (AGN) is believed to be fueled by the accretion of matter onto a supermassive black hole. This central accreting region of AGN has hitherto been spatially unresolved and its structure…

Astrophysics · Physics 2009-10-30 B. McKernan , T. Yaqoob

We analysed the centre of NGC 1566, which hosts a well-studied active galactic nucleus (AGN), known for its variability. With the aid of techniques such as Principal Component Analysis Tomography, analysis of the emission-line spectra,…

Astrophysics of Galaxies · Physics 2017-07-11 Patrícia da Silva , J. E. Steiner , R. B. Menezes

We present the analysis of an optical data cube of the central region of NGC 1448, obtained with the Multi Unit Spectroscopic Explorer (MUSE). Chandra X-ray data indicate that the active galactic nucleus (AGN) is not located at the apparent…

Astrophysics of Galaxies · Physics 2021-03-29 R. B. Menezes , Patrícia da Silva , J. E. Steiner

We investigate signs of Active Galactic Nucleus (AGN) in the luminous infrared galaxy NGC 3256 at both infrared and X-ray wavelengths. NGC 3256 has double, the Northern and Southern, nuclei (hereafter, N and S nuclei, respectively). We show…

Astrophysics of Galaxies · Physics 2015-06-03 Youichi Ohyama , Yuichi Terashima , Kazushi Sakamoto

We present deep Chandra X-ray observations of NGC 5005, a LINER-dominated galaxy previously reported to host a broad H$\alpha$ emission line. The diffuse soft X-ray emission ($<$3 keV) extends out to $\sim$800 pc, while harder emission…

Astrophysics of Galaxies · Physics 2025-09-26 Anna Trindade Falcão , R. Middei , G. Fabbiano , M. Elvis , P. Zhu , W. P. Maksym , D. Ł. Król , L. Feuillet

We present new HST NICMOS observations of NGC 4945, a starburst galaxy hosting a highly obscured active nucleus that is one of the brightest extragalactic sources at 100 keV. The HST data are complemented with ground based [FeII] line and…

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

Non-blazar Active Galactic Nuclei (AGN) have emerged as a new gamma-ray emitting source class on the extragalactic sky and started to deepen our understanding of the physical processes and the nature of AGN in general. The detection of…

High Energy Astrophysical Phenomena · Physics 2017-07-10 Frank M. Rieger

We report the discovery of a candidate active galactic nucleus (AGN), 2XMM J123103.2+110648 at z = 0.13, with an X-ray spectrum represented purely by soft thermal emission reminiscent of Galactic black hole (BH) binaries in the…

High Energy Astrophysical Phenomena · Physics 2015-06-05 Yuichi Terashima , Naoya Kamizasa , Hisamitsu Awaki , Aya Kubota , Yoshihiro Ueda

We conducted a Very Long Baseline Array (VLBA) observation of the low mass active galactic nucleus (AGN) in galaxy NGC 4293 ($z=0.003$). The object is associated with a low-ionization nuclear emission-line region (LINER). Its black hole…

Astrophysics of Galaxies · Physics 2022-11-16 Xiaolong Yang , Ruiling Wang , Quan Guo

We present 3-5 micron spectroscopy of the interacting system NGC 6240, showing the presence of two active galactic nuclei. The brightest (southern) nucleus shows up with a starburst-like emission, with a prominent 3.3 micron emission…

Astrophysics · Physics 2009-11-13 G. Risaliti , E. Sani , R. Maiolino , A. Marconi , S. Berta , V. Braito , R. Della Ceca , A. Franceschini , M. Salvati , .

Active galactic nuclei (AGN) are known to be variable sources across the entire electromagnetic spectrum, in particular at optical/ultraviolet and X-ray energies. Over the past decades, a growing number of AGN have displayed type…

Based on the dynamical black hole (BH) mass estimates, NGC3115 hosts the closest billion solar mass BH. Deep studies of the center revealed a very underluminous active galactic nucleus (AGN) immersed in an old massive nuclear star cluster.…

High Energy Astrophysical Phenomena · Physics 2015-06-16 Roman V. Shcherbakov , Ka-Wah Wong , Jimmy A. Irwin , Christopher S. Reynolds