14 papers
PEARLS: NuSTAR and XMM-Newton Extragalactic Survey of the JWST North Ecliptic Pole Time-Domain Field IV: X-Ray Variability Analysis
Ross Silver, Francesca Civano, Xiurui Zhao +31
NuSTAR and XMM-Newton have observed the James Webb Space Telescope (JWST) North Ecliptic Pole (NEP) Time-Domain Field (TDF) for almost five contiguous years starting in 2019. In th…
First Detection of Radio Polarization During Jet Formation in the Changing-Look AGN 1ES 1927+654
Onic I. Shuvo, Eileen T. Meyer, Sibasish Laha +10
We present a multiwavelength radio study of the changing-look AGN 1ES 1927+654 following its renewed X-ray brightening since mid-2022, combining VLBA imaging with multi-band and ti…
The emergence of X-ray emission lines during relativistic radio-jet formation in the changing-look active galactic nucleus 1ES 1927+654
Dev R. Sadaula, Sibasish Laha, Eileen T. Meyer +27
We present results from a comprehensive multi-wavelength monitoring campaign of the changing-look active galactic nucleus 1ES 1927+654 during the onset and evolution of a relativis…
The SKA-VLBI Perspective on Radio-Quiet AGN
Francesca Panessa, Tao An, James Petley +21
The accretion-ejection mechanism in Active Galactic Nuclei (AGN) remains a central open problem in astrophysics, tied to the role of AGN feedback in galaxy formation and evolution.…
Towards Instrument-Agnostic Exoplanet Candidate Prioritization
Vivaswan Kopparapu, Sibasish Laha, Brian P. Powell +3
We have developed a novel machine learning (ML) approach for predicting the likelihood of exoplanet candidate confirmation equally capable of performance on both TESS and Kepler da…
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…
PEARLS: NuSTAR and XMM-Newton Extragalactic Survey of the JWST North Ecliptic Pole Time-domain Field III
Ross Silver, Francesca Civano, Xiurui Zhao +28
The James Webb Space Telescope (JWST) North Ecliptic Pole (NEP) Time-Domain Field (TDF) has been monitored by NuSTAR and XMM-Newton with a regular cadence for five years starting i…
The 157-month Swift-BAT All-Sky Hard X-Ray Survey
Amy Y. Lien, Hans Krimm, Craig Markwardt +12
The Burst Alert Telescope (BAT) onboard the Neil Gehrels Swift observatory has been serving as a survey instrument for the hard X-ray sky, and has detected thousands of X-ray sourc…
The response of warm absorbers to the variations in the ionizing continuum in the active galaxy NGC 4051
Dev R Sadaula, Timothy R Kallman, Sibasish Laha
We present a time-resolved X-ray spectral analysis of the warm absorbers in the Seyfert galaxy NGC 4051, which has an active galactic nucleus (AGN), using observations from the Neu…
BatAnalysis -- A Comprehensive Python Pipeline for Swift BAT Time-Tagged Event Data Analysis
Tyler Parsotan, David M. Palmer, Samuele Ronchini +7
The Swift Burst Alert Telescope (BAT) is a coded aperture gamma-ray instrument with a large field of view that was designed to detect and localize transient events. When a transien…
Multi-wavelength observations of a jet launch in real time from the post-changing-look Active Galaxy 1ES 1927+654
Sibasish Laha, Eileen T. Meyer, Dev R. Sadaula +34
We present results from a high cadence multi-wavelength observational campaign of the enigmatic changing look AGN 1ES 1927+654 from May 2022- April 2024, coincident with an unprece…
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…
X-ray properties of coronal emission in radio quiet Active Galactic Nuclei
Sibasish Laha, Claudio Ricci, John C. Mather +5
Active galactic nuclei (AGN) are powerful sources of panchromatic radiation. All AGN emit in X-rays, contributing around of the AGN bolometric luminosity. The X-ray e…
Power of simultaneous X-ray and UV high-resolution spectroscopy for probing AGN outflows
Missagh Mehdipour, Laura W. Brenneman, Jon M. Miller +6
Black hole accretion in active galactic nuclei (AGN) is coupled to the evolution of their host galaxies. Outflowing winds in AGN can play an important role in this evolution throug…