activity
20242026
collaborators

7 papers

astro-ph.HE2026

Persistence of the Millihertz X-ray Quasi-Periodic Oscillation in the Active Galactic Nucleus 1ES 1927+654

Megan Masterson, Erin Kara, William N. Alston +15

1ES 1927+654 is an extreme active galactic nucleus (AGN) that has defied our canonical expectations for how AGN appear across the electromagnetic spectrum and how they vary on shor…

astro-ph.HE2025

A New Broadband Spectral State in the Ultraluminous X-ray Source Holmberg IX X-1

D. J. Walton, M. Bachetti, P. Kosec +12

We present a series of five new broadband X-ray observations of the ultraluminous X-ray source Holmberg IX X-1, performed by - and in coordination. The first…

astro-ph.HE2025

The Broadband View of the Bare Seyfert PG 1426+015: Relativistic Reflection, the Soft Excess and the Importance of Oxygen

D. J. Walton, A. Madathil-Pottayil, P. Kosec +8

We present results from a deep, coordinated - + observation of the type 1 Seyfert PG 1426+015, a source of particular interest as the most massive reverberati…

astro-ph.HE2025

Millihertz Oscillations Near the Innermost Orbit of a Supermassive Black Hole

Megan Masterson, Erin Kara, Christos Panagiotou +22

Recent discoveries from time-domain surveys are defying our expectations for how matter accretes onto supermassive black holes (SMBHs). The increased rate of short-timescale, repet…

astro-ph.HE2024

Effects of ultra-fast outflows on X-ray time lags in AGN

Yerong Xu, Ciro Pinto, Erin Kara +3

The time lag between soft and hard X-ray photons has been observed in many active galactic nuclei (AGN) and can reveal the accretion process and geometry around supermassive black…

astro-ph.HE2024

Exploring the high-density reflection model for the soft excess in RBS 1124

A. Madathil-Pottayil, D. J. Walton, Javier García +13

'Bare' active galactic nuclei (AGN) are a subclass of Type 1 AGN that show little or no intrinsic absorption. They offer an unobscured view of the central regions of the AGN and th…