activity
20202026
most citedThe nature of the extreme X-ray variability in the NLS1 1H 0707-495

32 citations · 95 across the 15 of their papers we have counts for

collaborators

16 papers

astro-ph.HE2026

Relativistic outflows power a quasi-periodic eruption: constraints on energetics, mass loss, and emission mechanisms

Joheen Chakraborty, Erin Kara, Wenbin Lu +17

Quasi-periodic eruptions (QPEs) are recurring bursts of X-ray radiation originating from supermassive black holes (SMBHs). They are an unprecedented type of structured, high-amplit…

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.HE2026★ 2 cited

XRISM finds the Changing-Look AGN NGC 1365 in an extended low state: A dense, highly ionized outflow obscures the central source

Fatima Zaidouni, Erin Kara, Peter Kosec +21

We present the first XRISM/Resolve observations of the active galactic nucleus, NGC 1365, obtained in 2024 February and July. NGC 1365 is known for rapid transitions between Compto…

astro-ph.GA2025

AGN STORM 2. XI. Spectroscopic reverberation mapping of the hot dust in Mrk 817

Hermine Landt, Benjamin D. Boizelle, Michael S. Brotherton +41

The AGN Space Telescope and Optical Reverberation Mapping 2 (STORM 2) campaign targeted Mrk 817 with intensive multi-wavelength monitoring and found its soft X-ray emission to be s…

astro-ph.GA2024

AGN STORM 2: X. The origin of the interband continuum delays in Mrk 817

Hagai Netzer, Michael R. Goad, Aaron J. Barth +26

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, w…

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.GA2024

The impact of void-finding algorithms on galaxy classification

Fatima Zaidouni, Dahlia Veyrat, Kelly A. Douglass +1

We explore how the definition of a void influences the conclusions drawn about the impact of the void environment on galactic properties using two void-finding algorithms in the Vo…

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.HE2021★ 32 cited

The nature of the extreme X-ray variability in the NLS1 1H 0707-495

M. L. Parker, W. N. Alston, L. Härer +11

We examine archival XMM-Newton data on the extremely variable narrow-line Seyfert 1 (NLS1) active galactic nucleus (AGN) 1H 0707-495. We construct fractional excess variance (Fvar)…

astro-ph.EP2020★ 4 cited

Accretion of Ornamental Equatorial Ridges on Pan, Atlas and Daphnis

Alice C. Quillen, Fatima Zaidouni, Miki Nakajima +1

We explore scenarios for the accretion of ornamental ridges on Saturn's moons Pan, Atlas, and Daphnis from material in Saturn's rings. Accretion of complex shaped ridges from ring…