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Repeated Partial Tidal Disruptions and Quasi-Periodic Eruptions in SwJ023017.0+283603
Dheeraj Pasham, Eric Coughlin, Chris Nixon +5
SwJ023017.0+283603 (SwJ0230) exhibited soft X-ray (0.3-1.0 keV) eruptions recurring roughly every 22 days. We present results from an extended monitoring campaign of SwJ0230 using…
Repeating transients in galactic nuclei: confronting observations with theory
Petra Suková, Francesco Tombesi, Dheeraj R. Pasham +5
In the last few years, a mysterious new class of astrophysical objects has been uncovered. These are spatially coincident with the nuclei of external galaxies and show X-ray variat…
Alive and Strongly Kicking: Stable X-ray Quasi-Periodic Eruptions from eRO-QPE2 over 3.5 Years
Dheeraj Pasham, Shubham Kejriwal, Eric Coughlin +5
Quasi-periodic eruptions (QPEs) are recurring bursts of soft X-rays from the nuclei of galaxies. Their physical origin is currently a subject of debate, with models typically invok…
The STROBE-X Wide Field Monitor Instrument
Ronald A. Remillard, Margarita Hernanz, Jean in 't Zand +26
The Wide Field Monitor (WFM) is one of the three instruments on the Spectroscopic Time-Resolving Observatory for Broadband Energy X-rays (STROBE-X) mission, which was proposed in r…
A long-duration superflare on the K giant HD 251108
Hans Moritz Günther, Dheeraj Pasham, Alexander Binks +10
Many giant stars are magnetically active, which causes rotational variability, chromospheric emission lines, and X-ray emission. Large outbursts in these emission features can set…
Characterization of a peculiar Einstein Probe transient EP240408a: an exotic gamma-ray burst or an abnormal jetted tidal disruption event?
B. O'Connor, D. Pasham, I. Andreoni +30
We present the results of our multi-wavelength (X-ray to radio) follow-up campaign of the Einstein Probe transient EP240408a. The initial 10 s trigger displayed bright soft X-ray (…
Revealing EMRI/IMRI candidates with quasiperiodic ultrafast outflows
Michal Zajaček, Petra Suková, Vladimír Karas +7
The first detection of the quasiperiodic ultrafast outflow in the ASASSN-20qc system was reported by Pasham et al. (2024). The outflow is revealed in the soft X-ray spectra as an a…
Quasi-periodic X-ray eruptions years after a nearby tidal disruption event
M. Nicholl, D. R. Pasham, A. Mummery +61
Quasi-periodic Eruptions (QPEs) are luminous bursts of soft X-rays from the nuclei of galaxies, repeating on timescales of hours to weeks. The mechanism behind these rare systems i…
A Potential Second Shutoff from AT2018fyk: An updated Orbital Ephemeris of the Surviving Star under the Repeating Partial Tidal Disruption Event Paradigm
Dheeraj Pasham, Eric Coughlin, Muryel Guolo +4
The tidal disruption event (TDE) AT2018dyk/ASASSN-18UL showed a rapid dimming event 500 days after discovery, followed by a re-brightening roughly 700 days later. It has been hypot…
Quasi-periodic X-ray eruptions and tidal disruption events prefer similar host galaxies
T. Wevers, K. D. French, A. I. Zabludoff +10
In the past five years, six quasi-periodic X-ray eruption (QPE) sources have been discovered in the nuclei of nearby galaxies. Their origin remains an open question. We present MUS…
Repeating nuclear transients from repeating partial tidal disruption events: reproducing ASASSN-14ko and AT2020vdq
Ananya Bandopadhyay, Eric R. Coughlin, C. J. Nixon +1
Some electromagnetic outbursts from the nuclei of distant galaxies have been found to repeat on months-to-years timescales, and each of these sources can putatively arise from the…
Sub-relativistic Outflow and Hours-Timescale Large-amplitude X-ray Dips during Super-Eddington Accretion onto a Low-mass Massive Black Hole in the Tidal Disruption Event AT2022lri
Yuhan Yao, Muryel Guolo, Francesco Tombesi +32
We present the tidal disruption event (TDE) AT2022lri, hosted in a nearby ( Mpc) quiescent galaxy with a low-mass massive black hole ($10^4\,M_\odot < M_{\rm BH} < 10…
Tidal disruption event AT2020ocn: early-time X-ray flares caused by a possible disc alignment process
Z. Cao, P. G. Jonker, D. R. Pasham +3
A tidal disruption event (TDE) may occur when a star is torn apart by the tidal force of a black hole (BH). Eventually, an accretion disc is thought to form out of stellar debris f…
AT2018fyk: Candidate Tidal Disruption Event by a (Super)massive Black Hole Binary
S. Wen, P. G. Jonker, A. J. Levan +8
The tidal disruption event (TDE) AT2018fyk has unusual X-ray, UV, and optical light curves that decay over the first 600d, rebrighten, and decay again around 1200d. We explai…
Late-time X-ray Observations of the Jetted Tidal Disruption Event AT2022cmc: The Relativistic Jet Shuts Off
T. Eftekhari, A. Tchekhovskoy, K. D. Alexander +9
The tidal disruption event (TDE) AT2022cmc represents the fourth known example of a relativistic jet produced by the tidal disruption of a stray star providing a unique probe of th…
Repeating Nuclear Transients as Candidate Electromagnetic Counterparts of LISA Extreme Mass Ratio Inspirals
Shubham Kejriwal, Vojtech Witzany, Michal Zajacek +2
Extreme-mass-ratio inspirals (EMRIs) are one of the primary targets for the recently adopted millihertz gravitational-wave (GW) observatory LISA. Some previous studies have argued…
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…
Alive but Barely Kicking: News from 3+ years of Swift and XMM-Newton X-ray Monitoring of Quasi-Periodic Eruptions from eRO-QPE1
Dheeraj R. Pasham, Eric R. Coughlin, Michal Zajacek +11
Quasi-periodic Eruptions (QPEs) represent a novel class of extragalactic X-ray transients that are known to repeat at roughly regular intervals of a few hours to days. Their underl…
Lense-Thirring Precession after a Supermassive Black Hole Disrupts a Star
Dheeraj R. Pasham, Michal Zajacek, C. J. Nixon +8
An accretion disk formed around a supermassive black hole (SMBH) after it disrupts a star is expected to be initially misaligned with respect to the black hole's equatorial plane.…
Episodic X-ray Outflows from the Tidal Disruption Event ASASSN-14li
Yukta Ajay, Dheeraj R. Pasham, Thomas Wevers +4
ASASSN-14li is a low-redshift () tidal disruption event (TDE) that has been studied extensively across the entire electromagnetic spectrum, and has provided one of the m…