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The local (z=0.0315) AGN Mrk 817, was monitored over more than 500 days with space-borne and ground-based instruments as part of a large international campaign AGN STORM 2. Here, we present a comprehensive analysis of the broad-band…

Variability studies are a powerful tool for studying the structures of unresolved sources. One such type of variability study, called reverberation mapping (RM), established that the dominant source of infrared radiation from an active…

Instrumentation and Methods for Astrophysics · Physics 2025-10-21 Varoujan Gorjian , Michael W. Werner

The dust reverberation mapping is one of powerful methods to investigate the structure of the dusty tori in AGNs, and it has been performed on more than a hundred type 1 AGNs. However, no clear results have been reported on type 2 AGNs…

Astrophysics of Galaxies · Physics 2020-05-27 Hirofumi Noda , Taiki Kawamuro , Mitsuru Kokubo , Takeo Minezaki

This work studies the relationship between accretion-disk size and quasar properties, using a sample of 95 quasars from the SDSS-RM project with measured lags between the $g$ and $i$ photometric bands. Our sample includes disk lags that are…

Active galactic nuclei (AGN) are high luminosity sources powered by accretion of matter onto SMBHs located at the centres of galaxies. The SMBH is surrounded by a broad emission line region (BLR) and a dusty torus. It is difficult to study…

Astrophysics of Galaxies · Physics 2019-05-07 Amit Kumar Mandal , Suvendu Rakshit , Indrani Pal , Chelliah Subramonian Stalin , Ram Sagar , Blesson Mathew

Reverberation mapping (RM) can measure black hole accretion disc sizes and radial structure through observed time lags that should increase with wavelength as $\tau\propto\lambda^{4/3}$. Our 250-day RM campaign on NGC 7469 combines sub-day…

We present a two-year optical reverberation mapping campaign of NGC 4051, an active galactic nucleus (AGN) hosting a low-mass black hole ($8\times10^5 M_\odot$), using daily observations in seven photometric bands from Las Cumbres…

We present the results of a two year optical continuum photometric reverberation mapping campaign carried out on the nucleus of the Seyfert-1 galaxy Mrk509. Specially designed narrow-band filters were used in order to mitigate the line and…

Astrophysics of Galaxies · Physics 2019-12-24 F. Pozo Nuñez , N. Gianniotis , J. Blex , T. Lisow , R. Chini , K. L. Polsterer , J. -U. Pott , J. Esser , G. Pietrzyński

Broad emission lines of active galactic nuclei (AGNs) originate from the broad-line region (BLR), consisting of dense gas clouds in orbit around an accreting supermassive black hole. Understanding the geometry and kinematics of the region…

Astrophysics of Galaxies · Physics 2024-08-29 Sha-Sha Li , Hai-Cheng Feng , H. T. Liu , J. M. Bai , Xiang Ji , Cheng Cheng , Kai-Xing Lu , Jian-Guo Wang , Rui Li

We present the results of a reverberation mapping (RM) campaign on the black hole (BH) associated with the active galactic nucleus (AGN) in SDSS J114008.71+030711.4 (hereafter GH08). This object is selected from a sample of 19 candidate…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 Stephen Rafter , Shai Kaspi , Ehud Behar , Wolfram Kollatschny , Matthias Zetzl

General relativistic ray tracing simulations of the time-averaged spectrum and energy-dependent time delays in AGN are presented. We model the lamp-post geometry in which the accreting gas is illuminated by an X-ray source located on the…

High Energy Astrophysical Phenomena · Physics 2016-07-27 P. Chainakun , A. J. Young , E. Kara

Active galactic nuclei (AGNs) are known to be variable across all wavelengths. Significant observational efforts have been invested in the last decade in studying their ultraviolet (UV) and optical variability. Long and densely sampled,…

High Energy Astrophysical Phenomena · Physics 2024-09-17 M. Papoutsis , I. E. Papadakis , C. Panagiotou , M. Dovčiak , E. Kammoun

For a compiled sample of 120 reverberation-mapped AGNs, the bivariate correlations of the broad-line regions (BLRs) size ($R_{\rm BLR}$) with the continuum luminosity at 5100 \AA\ ($L_{5100}$) and the dimensionless accretion rates…

Astrophysics of Galaxies · Physics 2020-01-08 Li-Ming Yu , Bi-Xuan Zhao , Wei-Hao Bian , Chan Wang , Xue Ge

Active galactic nuclei (AGN) with jets seen at small viewing angles are the most luminous and abundant objects in the $\gamma$-ray sky. AGN with jets misaligned along the line-of-sight appear fainter in the sky, but are more numerous than…

High Energy Astrophysical Phenomena · Physics 2015-06-15 M. Di Mauro , F. Calore , F. Donato , M. Ajello , L. Latronico

We present a thorough study of the Changing-Look Active Galactic Nucleus (CL-AGN) Mrk 1018, utilizing an extensive dataset spanning optical, UV, and X-ray spectro-photometric data from 2005 to 2019. We analysed X-ray spectra and broad-band…

High Energy Astrophysical Phenomena · Physics 2023-12-14 S. Veronese , C. Vignali , P. Severgnini , G. A. Matzeu , M. Cignoni

We present the results of a new reverberation mapping campaign for the broad-lined active galactic nucleus (AGN) in the edge-on spiral IC4329A. Monitoring of the optical continuum with $V-$band photometry and broad emission-line flux…

Astrophysics of Galaxies · Physics 2023-02-15 Misty C. Bentz , Christopher A. Onken , Rachel Street , Monica Valluri

The Lick AGN Monitoring Project targeted 13 nearby Seyfert 1 galaxies with the intent of measuring the masses of their central black holes using reverberation mapping. The sample includes 12 galaxies selected to have black holes with masses…

The size and structure of the dusty circumnuclear torus in active galactic nuclei (AGN) can be investigated by analyzing the temporal response of the torus's infrared (IR) dust emission to variations in the AGN ultraviolet/optical…

Astrophysics of Galaxies · Physics 2020-03-02 Triana Almeyda , Andrew Robinson , Michael Richmond , Robert Nikutta , Bryanne McDonough

We examine whether the spectral energy distribution of optical continuum emission of active galactic nuclei (AGNs) changes during flux variation, based on accurate and frequent monitoring observations of 11 nearby Seyfert galaxies and QSOs…

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