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 Lick AGN Monitoring Project 2016: velocity-resolved Hβ lags in luminous Seyfert galaxies

U Vivian, AJ Barth, HA Vogler, H Guo… - The Astrophysical …, 2022 - iopscience.iop.org
We carried out spectroscopic monitoring of 21 low-redshift Seyfert 1 galaxies using the Kast
double spectrograph on the 3 m Shane telescope at Lick Observatory from 2016 April to …

Revisiting UV/optical continuum time lags in AGN

ES Kammoun, L Robin, IE Papadakis… - Monthly Notices of …, 2023 - academic.oup.com
In this paper, we present an updated version of our model (KYN** project
designed to trace out the structure of Mrk 817 from the inner accretion disk to the broad …

Accretion disk size measurements of active galactic nuclei monitored by the Zwicky Transient Facility

WJ Guo, YR Li, ZX Zhang, LC Ho… - The Astrophysical …, 2022 - iopscience.iop.org
We compile a sample of 92 active galactic nuclei (AGNs) at z< 0.75 with gri photometric light
curves from the archival data of the Zwicky Transient Facility and measure the accretion disk …

Accretion disc sizes from continuum reverberation map** of AGN selected from the ZTF survey

VK Jha, R Joshi, H Chand, XB Wu… - Monthly Notices of …, 2022 - academic.oup.com
We present the accretion disc-size estimates for a sample of 19 active galactic nuclei (AGNs)
using the optical g-, r-, and i-band light curves obtained from the Zwicky Transient Facility …

Scientific objectives of the Hot Universe Baryon Surveyor (HUBS) mission

J Bregman, R Cen, Y Chen, W Cui, T Fang… - Science China Physics …, 2023 - Springer
Abstract The Hot Universe Baryon Surveyor (HUBS) is a proposed space-based X-ray
telescope for detecting X-ray emissions from the hot gas content in our universe. With its …

Changing-look event in NGC 3516: continuum or obscuration variability?

M Mehdipour, GA Kriss, LW Brenneman… - The Astrophysical …, 2022 - iopscience.iop.org
The Seyfert-1 galaxy NGC 3516 has undergone major spectral changes in recent years. In
2017 we obtained Chandra, NuSTAR, and Swift observations during its new low-flux state …

UV–optical disk reverberation lags despite a faint X-ray corona in the active galactic nucleus Mrk 335

E Kara, AJ Barth, EM Cackett, J Gelbord… - The Astrophysical …, 2023 - iopscience.iop.org
We present the first results from a 100-day Swift, NICER, and ground-based X-ray–UV–
optical reverberation map** campaign of the Narrow-line Seyfert 1 Mrk 335, when it was …

Estimating black hole spin from AGN SED fitting: the impact of general-relativistic ray tracing

S Hagen, C Done - Monthly Notices of the Royal Astronomical …, 2023 - academic.oup.com
Accretion disc model fitting to optical/UV quasar spectra requires that the highest mass black
holes have the highest spin, with implications on the hierarchical growth of supermassive …