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We have studied the molecular gas in the vicinity of low-luminosity active galactic nuclei (AGNs) in three bulge-less spiral galaxies: NGC 1042, NGC 4178, and NGC 4395. The (1-0) and (2-1) transitions of gaseous carbon monoxide (CO) are…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 Torsten Boeker , Eva Schinnerer , Ute Lisenfeld

NGC 4945 contains a well-known heavily obscured active galactic nucleus (AGN) at its core, with prior reports of strong nuclear and off-nuclear neutral Fe K$\alpha$ emission due to the AGN activity. We report the discovery of very extended…

We report a serendipitous discovery of six very low-luminosity active galactic nuclei (AGNs) only by optical variability in one-month baseline. The detected flux variability is ~ 1-5% of the total luminosity of host galaxies. Careful…

Astrophysics · Physics 2009-11-10 Tomonori Totani , Takahiro Sumi , George Kosugi , Naoki Yasuda , Mamoru Doi , Takeshi Oda

Kiloparsec-scale binary active galactic nuclei (AGNs) signal active supermassive black hole (SMBH) pairs in merging galaxies. Despite their significance, unambiguously confirmed cases remain scarce and most have been discovered…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 Xin Liu , Francesca Civano , Yue Shen , Paul J. Green , Jenny E. Greene , Michael A. Strauss

We report the detection of a gamma-ray spectral line at approximately 1.5 GeV in three active galactic nuclei (AGN) using 17 years of Fermi-LAT observations. The sample includes both blazars (with relativistic jets directed toward Earth)…

High Energy Astrophysical Phenomena · Physics 2026-04-02 Shi-Ju Kang , Yue Yin , Yong-Gang Zheng , Qingwen Wu

We have discovered a binary AGN in the galaxy Mrk 739 using Chandra and Swift BAT. We find two luminous L_2-10 keV=1.1*10^43 and 1.0*10^42 erg/s, unresolved nuclei with a projected separation of 3.4 kpc (5.8\pm0.1) coincident with two bulge…

The most rapidly evolving regions of galaxies often display complex optical spectra with emission lines excited by massive stars, shocks and accretion onto supermassive black holes. Standard calibrations (such as for the star formation…

PKS J2310-437 is an AGN with bright X-ray emission relative to its weak radio emission and optical continuum. It is believed that its jet lies far enough from the line of sight that it is not highly relativistically beamed. It thus provides…

High Energy Astrophysical Phenomena · Physics 2009-11-16 A. F. Bliss , D. M. Worrall , M. Birkinshaw , S. S. Murray , H. Tananbaum

The discovery over the last several decades of moderate luminosity AGNs in disk-dominated galaxies - which show no "classical" bulges - suggests that secular mechanisms represent an important growth pathway for supermassive black holes in…

We report the results of an investigation to determine the nature of the offset active galactic nucleus (AGN) found in the source CXO J101527.2+625911. Hubble Space Telescope and Chandra X-ray observatory data had suggested that the offset…

Astrophysics of Galaxies · Physics 2019-09-25 D. -C. Kim , E. Momjian , Ilsang Yoon , Minjin Kim , A. S. Evans , Ji Hoon Kim , S. T. Linden , L. Barcos-Munoz , G. C. Privon

We used the NSF Jansky Very Large Array at a frequency $\nu =$ 22\,GHz to study the nearest billion-solar-mass black hole, in the early-type galaxy NGC\,3115 at a distance of 9.7\,Mpc. We localize a faint continuum nucleus, with flux…

Astrophysics of Galaxies · Physics 2025-08-12 J. M. Wrobel , D. W. Pesce , K. E. Nyland

We present a deep (~5.8 days) 0.3-2 keV high-resolution spectrum of NGC1365, collected with the reflection grating spectrometer (RGS) on board XMM-Newton. The spectrum is dominated by strong recombination lines of He- and H-like transitions…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 M. Guainazzi , G. Risaliti , A. Nucita , Junfeng Wang , S. Bianchi , R. Soria , A. Zezas

Active Galactic Nuclei (AGN) show excess X-ray emission above 10 keV compared with extrapolation of spectra from lower energies. Risaliti et al. have recently attempted to model the hard X-ray excess in the type 1.8 AGN NGC 1365, concluding…

High Energy Astrophysical Phenomena · Physics 2013-08-01 L. Miller , T. J. Turner

HST UV STIS imaging and spectroscopy of the low luminosity AGN (LLAGN) NGC 4303 have identified the previously detected UV-bright nucleus of this galaxy, as a compact, massive and luminous stellar cluster. The cluster with a size (FWHM) of…

Astrophysics · Physics 2009-11-07 Luis Colina , Rosa Gonzalez Delgado , Miguel Mas-Hess , Claus Leitherer

(ABRIDGED) AIMS: We searched for X-ray signatures of AGN in a sample of star-forming, relatively early-type, nearby spiral galaxies. Such galaxies are likely to host nuclear super-massive black holes. METHODS: For 9 sources from the Ho et…

Astrophysics · Physics 2008-11-26 P. Tzanavaris , I. Georgantopoulos

In a 52 ks-long Chandra ACIS-S observation of the nearby starburst galaxy NGC 3628, obtained to study the starburst-driven outflow from this galaxy, we have detected a very luminous (L_X = 1.1e40 erg/s in the 0.3-8.0 keV energy band) point…

During galaxy merger events, the supermassive black holes in the center of the galaxies may form a pair of active galactic nuclei (AGN) with kpc-scale or even pc-scale separation. Recently, optical observations revealed a promising dual AGN…

Astrophysics of Galaxies · Physics 2021-12-22 Patrik Milán Veres , Krisztina É. Gabányi , Sándor Frey , Zsolt Paragi , Emma Kun , Tao An

A new radio map of the Abell 85 Brightest Cluster Galaxy (BCG) was obtained with the Karl G. Jansky Very Large Array (VLA). With a resolution of 0.02", this radio image shows two kiloparsec-scale bipolar jets emanating from the active…

Astrophysics of Galaxies · Physics 2020-12-22 Juan P. Madrid

We report the results of the {\it Chandra} ACIS-S observations of the elliptical galaxy NGC 821, which harbors a supermassive nuclear black hole (of $3.5 \times 10^7 M_{\odot}$), but does not show sign of AGN activity. A small,…

Astrophysics · Physics 2015-06-24 G. Fabbiano , A. Baldi , S. Pellegrini , A. Siemiginowska , M. Elvis , A. Zezas , J. McDowell