activity
20212026
most citedDiscovery of the luminous X-ray ignition eRASSt J234402.9352640; I. Tidal disruption event or a rapid increase in accretion in an active galactic nucleus?

25 citations · 101 across the 14 of their papers we have counts for

collaborators

14 papers

astro-ph.GA2026

AGN STORM 2. XII. Ground-Based Optical Photometry and Lag Measurements of Mrk 817

John W. Montano, Aaron J. Barth, Keith Horne +40

We present the ground-based imaging campaign and light curves of Markarian 817 as part of the multiwavelength monitoring program AGN STORM\,2. Observations were carried out over 1.…

astro-ph.HE2025★ 1 cited

Untangling the Complex Nature of AGN Variability with Fairall 9

Scott Hagen, Chris Done, Edward M. Cackett +5

The accretion flow in AGN is not well understood, motivating intensive monitoring campaigns of multiwavelength variability to probe its structure. One of the best of these is the 3…

astro-ph.HE2025★ 3 cited

Testing X-ray Reprocessing and Mapping the Soft Excess of NGC 7469 with NICER

Ethan R. Partington, Edward M. Cackett, Rick Edelson +5

We present an X-ray/UV reverberation analysis of NGC 7469 across 210 days, using daily NICER observations with contemporaneous monitoring by Swift UVOT+XRT. We model the X-ray spec…

astro-ph.HE2024★ 9 cited

Connecting the X-ray/UV variability of Fairall 9 with NICER: A Possible Warm Corona

Ethan R. Partington, Edward M. Cackett, Rick Edelson +7

The Seyfert 1 AGN Fairall 9 was targeted by NICER, Swift, and ground-based observatories for a 1000-day long reverberation mapping campaign. The following analysis of NICER s…

astro-ph.HE2024★ 20 cited

AGN STORM 2. VII. A Frequency-resolved Map of the Accretion Disk in Mrk 817: Simultaneous X-ray Reverberation and UVOIR Disk Reprocessing Time Lags

Collin Lewin, Erin Kara, Aaron J. Barth +35

X-ray reverberation mapping is a powerful technique for probing the innermost accretion disk, whereas continuum reverberation mapping in the UV, optical, and infrared (UVOIR) revea…

astro-ph.GA2024

AGN STORM 2: VIII. Investigating the Narrow Absorption Lines in Mrk 817 Using HST-COS Observations

Maryam Dehghanian, Nahum Arav, Gerard A. Kriss +39

We observed the Seyfert 1 galaxy Mrk817 during an intensive multi-wavelength reverberation mapping campaign for 16 months. Here, we examine the behavior of narrow UV absorption lin…

astro-ph.HE2024

AGN STORM 2: IX. Studying the Dynamics of the Ionized Obscurer in Mrk 817 with High-resolution X-ray Spectroscopy

Fatima Zaidouni, Erin Kara, Peter Kosec +45

We present the results of the XMM-Newton and NuSTAR observations taken as part of the ongoing, intensive multi-wavelength monitoring program of the Seyfert 1 galaxy Mrk 817 by the…

astro-ph.HE2023

AGN STORM 2. VI. Mapping Temperature Fluctuations in the Accretion Disk of Mrk 817

Jack M. M. Neustadt, Christopher S. Kochanek, John Montano +49

We fit the UV/optical lightcurves of the Seyfert 1 galaxy Mrk 817 to produce maps of the accretion disk temperature fluctuations resolved in time and radius. The maps are…

astro-ph.GA2023

AGN STORM 2: V. Anomalous Behavior of the CIV Light Curve in Mrk 817

Y. Homayouni, Gerard A. Kriss, Gisella De Rosa +49

An intensive reverberation mapping campaign on the Seyfert 1 galaxy Mrk817 using the Cosmic Origins Spectrograph (COS) on the Hubble Space Telescope (HST) revealed significant vari…

astro-ph.HE2023

AGN STORM 2. IV. Swift X-ray and ultraviolet/optical monitoring of Mrk 817

Edward M. Cackett, Jonathan Gelbord, Aaron J. Barth +48

The AGN STORM 2 campaign is a large, multiwavelength reverberation mapping project designed to trace out the structure of Mrk 817 from the inner accretion disk to the broad emissio…

astro-ph.HE2023★ 20 cited

AGN STORM 2. III. A NICER view of the variable X-ray obscurer in Mrk 817

Ethan R. Partington, Edward M. Cackett, Erin Kara +44

The AGN STORM 2 collaboration targeted the Seyfert 1 galaxy Mrk 817 for a year-long multiwavelength, coordinated reverberation mapping campaign including HST, Swift, XMM-Newton, NI…

astro-ph.GA2023★ 17 cited

AGN STORM 2: II. Ultraviolet Observations of Mrk817 with the Cosmic Origins Spectrograph on the Hubble Space Telescope

Y. Homayouni, Gisella De Rosa, Rachel Plesha +62

We present reverberation mapping measurements for the prominent ultraviolet broad emission lines of the active galactic nucleus Mrk817 using 165 spectra obtained with the Cosmic Or…

astro-ph.HE2023★ 25 cited

Discovery of the luminous X-ray ignition eRASSt J234402.9352640; I. Tidal disruption event or a rapid increase in accretion in an active galactic nucleus?

D. Homan, M. Krumpe, A. Markowitz +17

In November 2020, a new, bright object, eRASSt J234402.9352640, was discovered in the second all-sky survey of SRG/eROSITA. The object brightened by a factor of at least 150 in…

astro-ph.HE2021★ 6 cited

AGN STORM 2: I. First results: A Change in the Weather of Mrk 817

Erin Kara, Missagh Mehdipour, Gerard A. Kriss +69

We present the first results from the ongoing, intensive, multi-wavelength monitoring program of the luminous Seyfert 1 galaxy Mrk 817. While this AGN was, in part, selected for it…