137 citations · 327 across the 26 of their papers we have counts for
26 papers
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…
A Suppressed Volumetric Rate of High-Luminosity Mid-Infrared Selected Tidal Disruption Events
Prajna Nair, Christos Panagiotou, Megan Masterson +4
Tidal Disruption Events (TDEs) serve as direct probes of the population of supermassive black holes in the center of galaxies and are nowadays regularly detected in optical wide-fi…
Fading into darkness: A weak mass ejection and low-efficiency fallback accompanying black hole formation in M31-2014-DS1
Kishalay De, Morgan MacLeod, Jacob E. Jencson +10
Stellar-mass black holes (BHs) can form from the near-complete collapse of massive stars, causing them to abruptly disappear. The star M31-2014-DS1 in the Andromeda galaxy was repo…
X-ray Spectral-Timing Properties of Tidal Disruption Events
Joheen Chakraborty, Megan Masterson, Andrew Mummery +4
We perform the first systematic study of the minute-to-hours-timescale stochastic variability observed in the X-ray luminosity of tidal disruption events (TDEs) using XMM-Newton da…
Testing the Association of Supermassive Black Hole Infrared Flares and High-energy Neutrinos
Megan Wang, Christos Panagiotou, Kishalay De +3
The physical origin of the observed cosmic neutrinos remains an open question and the subject of active research. While matter accretion onto supermassive black holes is long thoug…
Disk-to-Corona State Transition and Extreme X-ray Variability in the Tidal Disruption Event AT2019teq
Vera Berger, Erin Kara, Joheen Chakraborty +2
We present a five-year X-ray spectral and timing analysis of the optically selected Tidal Disruption Event (TDE) AT2019teq, which displays extreme variability, including order-of-m…
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…
GRB 250702B: Discovery of a Gamma-Ray Burst from a Black Hole Falling into a Star
Eliza Neights, Eric Burns, Chris L. Fryer +52
Gamma-ray bursts are the most luminous electromagnetic events in the universe. Their prompt gamma-ray emission has typical durations between a fraction of a second and several minu…
Radio Emission from the Infrared Tidal Disruption Event WTP14adeqka: The First Directly Resolved Delayed Outflow from a TDE
Walter W. Golay, Edo Berger, Yvette Cendes +10
We present detailed radio observations of the mid-infrared (MIR) tidal disruption event (TDE) WTP14adeqka. We detect rising radio emission starting years after the disc…
JWST's First View of Tidal Disruption Events: Compact, Accretion-Driven Emission Lines & Strong Silicate Emission in an Infrared-selected Sample
Megan Masterson, Kishalay De, Christos Panagiotou +7
Mid-infrared (MIR) emission from tidal disruption events (TDEs) is a powerful probe of the circumnuclear environment around dormant supermassive black holes. This emission arises f…
High-Frequency Power Spectrum of AGN NGC 4051 Revealed by NICER
B. Rani, Jungeun Kim, I. Papadakis +6
Variability studies offer a compelling glimpse into black hole dynamics, and NICER's (Neutron Star Interior Composition Explorer) remarkable temporal resolution propels us even fur…
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…
Disappearance of a massive star in the Andromeda Galaxy due to formation of a black hole
Kishalay De, Morgan MacLeod, Jacob E. Jencson +11
When a massive star reaches the end of its lifetime, its core collapses and releases neutrinos that drive a shock into the outer layers (stellar envelope). A sufficiently strong sh…
Late-time radio brightening and emergence of a radio jet in the changing-look AGN 1ES 1927+654
Eileen T. Meyer, Sibasish Laha, Onic I. Shuvo +32
We present multi-frequency (5-345 GHz) and multi-resolution radio observations of 1ES 1927+654, widely considered one of the most unusual and extreme changing-look active galactic…
WTP19aalnxx: Discovery of a bright mid-infrared transient in the emerging class of low luminosity supernovae revealed by delayed circumstellar interaction
Charlotte Myers, Kishalay De, Lin Yan +11
While core-collapse supernovae (SNe) often show early and consistent signs of circumstellar (CSM) interaction, some exhibit delayed signatures due to interaction with distant mater…
A Case for a Binary Black Hole System Revealed via Quasi-Periodic Outflows
Dheeraj R. Pasham, Francesco Tombesi, Petra Sukova +33
Binaries containing a compact object orbiting a supermassive black hole are thought to be precursors of gravitational wave events, but their identification has been extremely chall…
A New Population of Mid-Infrared-Selected Tidal Disruption Events: Implications for Tidal Disruption Event Rates and Host Galaxy Properties
Megan Masterson, Kishalay De, Christos Panagiotou +14
Most tidal disruption events (TDEs) are currently found in time-domain optical and soft X-ray surveys, both of which are prone to significant obscuration. The infrared (IR), howeve…
Rapid dimming followed by a state transition: a study of the highly variable nuclear transient AT 2019avd over 1000+ days
Yanan Wang, Dheeraj R. Pasham, Diego Altamirano +16
The tidal disruption of a star around a supermassive black hole (SMBH) offers a unique opportunity to study accretion onto a SMBH on a human-timescale. We present results from our…
A luminous dust-obscured Tidal Disruption Event candidate in a star forming galaxy at 42 Mpc
Christos Panagiotou, Kishalay De, Megan Masterson +11
While the vast majority of Tidal Disruption Events (TDEs) has been identified by wide-field sky surveys in the optical and X-ray bands, recent studies indicate that a considerable…
Unusual Hard X-ray Flares Caught in NICER Monitoring of the Binary Supermassive Black Hole Candidate AT2019cuk/Tick Tock/SDSS J1430+2303
Megan Masterson, Erin Kara, Dheeraj R. Pasham +17
The nuclear transient AT2019cuk/Tick Tock/SDSS J1430+2303 has been suggested to harbor a supermassive black hole (SMBH) binary near coalescence. We report results from high-cadence…
UV/Optical disk reverberation lags despite a faint X-ray corona in the AGN Mrk 335
Erin Kara, Aaron J. Barth, Edward M. Cackett +37
We present the first results from a 100-day Swift, NICER and ground-based X-ray/UV/optical reverberation mapping campaign of the Narrow-Line Seyfert 1 Mrk 335, when it was in an un…
Evidence for AGN-Regulated Cooling in Clusters at : A Multi-Wavelength View of SPT-CL J0607-4448
Megan Masterson, Michael McDonald, Behzad Ansarinejad +9
We present a multi-wavelength analysis of the galaxy cluster SPT-CL J0607-4448 (SPT0607), which is one of the most distant clusters discovered by the South Pole Telescope (SPT) at…
Probing the Extent of Fe K Emission in Nearby Active Galactic Nuclei using Multi-Order Analysis of Chandra High Energy Transmission Grating Data
Megan Masterson, Christopher S. Reynolds
We present a study of the narrow Fe K line in seven bright, nearby AGN that have been observed extensively with the Chandra High Energy Transmission Grating (HETG). The HETG dat…
Evolution of a Relativistic Outflow and X-ray Corona in the Extreme Changing-Look AGN 1ES 1927+654
Megan Masterson, Erin Kara, Claudio Ricci +8
1ES 1927+654 is a paradigm-defying AGN and one of the most peculiar X-ray nuclear transients. In early 2018, this well-known AGN underwent a changing-look event, in which broad opt…