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We present the results of a joint {\it XMM-Newton} and {\it NuSTAR} campaign on the active galactic nucleus (AGN) IC 4329A, consisting of 9 $\times$ 20 ks {\it XMM-Newton} observations, and 5 $\times$ 20 ks {\it NuSTAR} observations within…

Active galactic nuclei (AGNs) exhibit variability in their luminosities with timescales that correlate with the mass of the black hole at the centre of the AGN. Presently, the empirical correlation lacks sufficient precision to confidently…

Astrophysics of Galaxies · Physics 2025-12-22 Adrien Hélias , Sarah C. Gallagher , Pauline Barmby

High-resolution X-ray observations offer a unique tool for probing the still elusive connection between galaxy mergers and active galactic nuclei (AGNs). We present an analysis of nuclear X-ray emission in an optically selected sample of 92…

Astrophysics of Galaxies · Physics 2023-06-07 Lin He , Meicun Hou , Zhiyuan Li , Shuai Feng , Xin Liu

We conduct an analysis of over 60,000 dwarf galaxies (7<=log(M_*/M_\odot)<=10) in search of photometric variability indicative of active galactic nuclei (AGNs). Using data from the Young Supernova Experiment (YSE), a time domain survey on…

There is increasing evidence to suggest that AGN activity may be episodic, with a wide range of possible time scales. Radio galaxies exhibit the most striking examples of episodic activity, with two or three distinct pairs of lobes on…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-19 D. J. Saikia , M. Jamrozy , C. Konar , S. Nandi

"Changing-look" active galactic nuclei (CL-AGNs) are a newly-discovered class of AGNs that show the appearance (or disappearance) of broad emission lines within a short time scale (months to years) and are often associated with the dramatic…

Astrophysics of Galaxies · Physics 2022-03-09 Jun-Jie Jin , Xue-Bing Wu , Xiao-Tong Feng

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

Active Galactic Nuclei (AGN) are axisymmetric systems to first order; their observed properties are likely strong functions of inclination with respect to our line of sight, yet the specific inclinations of all but a few AGN are generally…

Astrophysics of Galaxies · Physics 2015-06-18 T. C. Fischer , D. M. Crenshaw , S. B. Kraemer , H. R. Schmitt , T. J. Turner

We discuss the spectral analysis of a sample of 63 Active Galactic Nuclei (AGN) detected above a limiting flux of $S(8-24$ keV$)=7\times10^{-14}$ erg/s/cm$^2$ in the multi-tiered NuSTAR Extragalactic Survey program. The sources span a…

We present a study of variability time scales in a large sample of Active Galactic Nuclei at several frequencies between 4.8 and 230 GHz. We investigate the differences of various AGN types and frequencies and correlate the measured time…

It is commonly accepted that active galactic nuclei (AGN) have a strong impact upon the evolution of their host galaxies, but the processes by which they do so are not fully understood. We aim to further the understanding of AGN feeding and…

Astrophysics of Galaxies · Physics 2025-01-22 Sophie L. Robbins , Sandra I. Raimundo , Matthew A. Malkan

The application of multi-wavelength selection techniques is crucial for discovering a complete and unbiased set of Active Galactic Nuclei (AGNs). Here, we select a sample of 72 AGN candidates in the Extended Groth Strip (EGS) using deep…

Observations and detections of Active Galactic Nuclei (AGN) by Cherenkov telescopes are often triggered by information about high flux states in other wavelength bands. To overcome this bias, the VHE gamma-ray telescope MAGIC has conducted…

We present a sample of 47 confirmed and 14 candidate Active Galactic Nuclei (AGN) discovered in the Canadian Network for Observational Cosmology field galaxy redshift survey (CNOC2). The sample consists of 38 objects identified from broad…

The relationships between galaxies of intermediate stellar mass and moderate luminosity active galactic nuclei (AGNs) at 1<z<3 are investigated with the Galaxy Mass Assembly ultra-deep Spectroscopic Survey (GMASS) sample complemented with…

Astrophysics of Galaxies · Physics 2015-06-17 A. Cimatti , M. Brusa , M. Talia , M. Mignoli , G. Rodighiero , J. Kurk , P. Cassata , C. Halliday , A. Renzini , E. Daddi

The unified model of active galactic nuclei (AGN) claims that the properties of AGN depend on the viewing angle of the observer with respect to a toroidal distribution of dust surrounding the nucleus. Both the mid-infrared (MIR) attenuation…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 O. Gonzalez-Martin , J. M. Rodriguez-Espinosa , T. Diaz-Santos , C. Packham , A. Alonso-Herrero , P. Esquej , C. Ramos Almeida , R. Mason , C. Telesco

Active galactic nuclei (AGN) are powered by the accretion of disks of gas onto supermassive black holes (SMBHs). Stars and stellar remnants orbiting the SMBH in the nuclear star cluster (NSC) will interact with the AGN disk. Orbiters…

Astrophysics of Galaxies · Physics 2020-11-02 Gaia Fabj , Syeda S. Nasim , Freddy Caban , K. E. Saavik Ford , Barry McKernan , Jillian M. Bellovary

Changing-look Active Galactic Nuclei (CL AGNs) exhibit drastic variations in broad emission lines (BELs), the mechanism of which remains unclear. Expanding the sample of CL AGNs is helpful to reveal the mechanism. This study aims to…

Astrophysics of Galaxies · Physics 2025-04-24 Qian Dong , Zhi-Xiang Zhang , Wei-Min Gu , Mouyuan Sun , Yong-Gang Zheng

The majority of the active galactic nuclei (AGN) detected at very-high-energies above 100 GeV belong to the class of blazars with a small angle between the jet-axis and the line-of-sight. Only about 10 percent of the gamma-ray AGN are…

High Energy Astrophysical Phenomena · Physics 2021-08-04 Dorit Glawion , Alicja Wierzcholska

We constrain the number density and evolution of Compton-thick Active Galactic Nuclei (AGN), and their contribution to the extragalactic X-ray background. In the local Universe we use the wide area surveys from the Swift and INTEGRAL…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 E. Treister , C. M. Urry , C. Cardamone , S. Virani , K. Schawinski , E. Gawiser