Changing-look active galactic nuclei

C Ricci, B Trakhtenbrot - Nature Astronomy, 2023‏ - nature.com
Active galactic nuclei (AGNs) are known to show flux variability over all observable
timescales and across the entire electromagnetic spectrum. Over the past decade, a growing …

The Galaxy Activity, Torus, and Outflow Survey (GATOS)-I. ALMA images of dusty molecular tori in Seyfert galaxies

S García-Burillo, A Alonso-Herrero, CR Almeida… - Astronomy & …, 2021‏ - aanda.org
We present the first results of the Galaxy Activity, Torus, and Outflow Survey (GATOS), a
project aimed at understanding the properties of the dusty molecular tori and their …

WISE view of changing-look active galactic nuclei: evidence for a transitional stage of AGNs

B Lyu, Q Wu, Z Yan, W Yu, H Liu - The Astrophysical Journal, 2022‏ - iopscience.iop.org
The discovery of changing-look active galactic nuclei (CLAGNs) with a significant change in
optical broad emission lines (optical CLAGNs) and/or strong variation of line-of-sight column …

Survey of Bare Active Galactic Nuclei in the Local Universe (z< 0.2). I. On the Origin of Soft Excess

P Nandi, A Chatterjee, A Jana… - The Astrophysical …, 2023‏ - iopscience.iop.org
We analyze a sample of 21" bare" Seyfert 1 active galactic nuclei, a subclass of Seyfert 1
galaxies, with intrinsic absorption NH∼ 10 20 cm− 2, in the local Universe (z< 0.2) using …

Coronal properties of low-accreting AGNs using Swift, XMMNewton, and NuSTAR observations

A Jana, A Chatterjee, HK Chang… - Monthly Notices of …, 2023‏ - academic.oup.com
We studied the broad-band X-ray spectra of Swift/Burst Alert Telescope selected low-
accreting active galactic nuclei (AGNs) using the observations from XMM–Newton, Swift …

Investigating changing-look active galactic nuclei with long-term optical and X-ray observations

A Jana, C Ricci, MJ Temple, HK Chang… - Astronomy & …, 2025‏ - aanda.org
Context. Broad emission lines in the UV/optical spectra of changing-look active galactic
nuclei (CLAGNs) appear and disappear on timescales of months to decades. Aims. We …

Broad-band X-ray observations of the 2018 outburst of the changing-look active galactic nucleus NGC 1566

A Jana, N Kumari, P Nandi, S Naik… - Monthly Notices of …, 2021‏ - academic.oup.com
We study the nature of the changing-look active galactic nucleus NGC 1566 during its 2018
June outburst. During the outburst, the X-ray intensity of the source rises up to∼ 25–30 …

Hydrogen column density variability in a sample of local Compton-thin AGN

N Torres-Albà, S Marchesi, X Zhao, I Cox… - Astronomy & …, 2023‏ - aanda.org
We present the analysis of multiepoch observations of a set of 12 variable, Compton-thin,
local (z< 0.1) active galactic nuclei (AGN) selected from the 100-month BAT catalog. We …

Long-term X-ray temporal and spectral study of a Seyfert galaxy Mrk 6

N Layek, P Nandi, S Naik, N Kumari… - Monthly Notices of …, 2024‏ - academic.oup.com
We present a long-term X-ray study of a nearby Active Galactic Nucleus Mrk 6, utilizing
observations from XMM–Newton, Suzaku, Swift, and NuSTAR observatories, spanning 22 …

Long-term X-ray observations of seyfert 1 galaxy ark 120: on the origin of soft-excess

P Nandi, A Chatterjee, SK Chakrabarti… - Monthly Notices of the …, 2021‏ - academic.oup.com
We present the long-term X-ray spectral and temporal analysis of a 'bare-type AGN'Ark 120.
We consider the observations from XMM–Newton, Suzaku, Swift, and NuSTAR from 2003 to …