A5040031731- Pulsars and Gravitational Waves Research
- Cosmology and Gravitation Theories
- Astrophysical Phenomena and Observations
- Gamma-ray bursts and supernovae
- Astrophysics and Cosmic Phenomena
- Black Holes and Theoretical Physics
- Seismology and Earthquake Studies
- Superconducting Materials and Applications
- High-pressure geophysics and materials
- Risk Perception and Management
- Mechanics and Biomechanics Studies
- Health and Medical Research Impacts
- Tropical and Extratropical Cyclones Research
- Radio Astronomy Observations and Technology
- Digital Humanities and Scholarship
- Methane Hydrates and Related Phenomena
- Library Collection Development and Digital Resources
- History and Developments in Astronomy
- Noncommutative and Quantum Gravity Theories
University of Toronto
2019-2022
Canadian Institute for Theoretical Astrophysics
2022
McGill University
2017-2018
University of Waterloo
2017
In classical General Relativity (GR), an observer falling into astrophysical black hole is not expected to experience anything dramatic as she crosses the event horizon. However, tentative resolutions problems in quantum gravity, such cosmological constant problem, or information paradox, invoke significant departures from classicality vicinity of It was recently pointed out that near-horizon structures can lead late-time echoes merger gravitational wave signals are otherwise...
In a recent paper (arXiv:1612.00266), we reported the results of first search for echoes from Planck-scale modifications general relativity near black hole event horizons using public data release by Advanced LIGO gravitational wave observatory. While found tentative evidence (at $\simeq 3 σ$ level) presence these echoes, our statistical methodology was challenged Ashton, et al. (arXiv:1612.05625), just in time holidays! this short note, briefly address criticisms, arguing that they either...
We construct a class of five dimensional black hole solutions to cubic quasi-topological gravity with conformal scalar hair and study their thermodynamics. find these holes provide the second example $λ$-lines: line order (continuous) phase transitions, akin fluid/superfluid transition $^4$He. Examples isolated critical points are found for spherical holes, marking first in literature date. also various novel interesting structures, including an point occurring conjunction double reentrant...
In a recent publication (1612.00266), we demonstrated that the events in first observing run of Advanced LIGO gravitational wave observatory (aLIGO O1) showed tentative evidence for repeating "echoes from abyss" caused by Planck-scale structure near black hole horizons. By considering phenomenological echo model, pure noise hypothesis is disfavored with p-value 1%, i.e. higher amplitude echoes than those aLIGO O1 are only recovered 1% random realizations. A preprint Westerweck, et al....
Abstract We present the discovery of fading radio transient FIRST J153350.8+272729. The source had a maximum observed 5 GHz luminosity 8 × 10 39 erg s −1 in 1986, but by 2019 faded factor nearly 400. It is located at center galaxy (SDSS J153350.89+272729) 147 Mpc, which shows weak Type II Seyfert activity. show that tidal disruption event (TDE) preferred scenario for J153350.8+272729, although it could plausibly be interpreted as afterglow long-duration γ -ray burst. This only second TDE...
Abstract Late-time (∼a year) radio follow-up of optically discovered tidal disruption events (TDEs) is increasingly resulting in detections at wavelengths, and there growing evidence for this late-time activity to be common the broad class subrelativistic TDEs. Detailed studies some these TDEs wavelengths are also challenging existing models emission. Using all-sky multiepoch data from Australian Square Kilometre Array Pathfinder (ASKAP), taken as a part Rapid ASKAP Continuum Survey (RACS),...
Abstract We report NuSTAR and Chandra observations of two X-ray transients, SWIFT J174540.7−290015 (T15) J174540.2−290037 (T37), which were discovered by the Neil Gehrels Swift Observatory in 2016 within r ∼ 1 pc Sgr A*. detected bright outbursts from T15 T37, likely soft hard states, with 3–79 keV luminosities 8 × 10 36 3 37 erg s −1 , respectively. No have previously been transients our ACIS analysis puts an upper limit L X ≲ 2 31 on their quiescent 2–8 luminosities. pulsations,...
We present a systematic search for tidal disruption events (TDEs) using radio data from the Variables and Slow Transients (VAST) Pilot Survey conducted Australian Square Kilometre Array Pathfinder (ASKAP). Historically, TDEs have been identified observations at X-ray, optical, ultraviolet wavelengths. After discovery, few dozen shown to counterparts through follow-up observations. With time-domain surveys becoming available, we can now identify new in regime. A population of radio-discovered...
Abstract We present a systematic search for tidal disruption events (TDEs) using radio data from the Variables and Slow Transients (VAST) Pilot Survey conducted Australian Square Kilometre Array Pathfinder. Historically, TDEs have been identified observations at X-ray, optical, ultraviolet wavelengths. After discovery, few dozen shown to counterparts through follow-up observations. With time-domain surveys becoming available, we can now identify new in regime. A population of...
We present a detailed analysis of AT 2020nov, tidal disruption event (TDE) in the center its host galaxy, located at redshift $z = 0.083$. 2020nov exhibits unique features, including double-peaked Balmer emission lines, broad UV/optical flare, and peak log luminosity extreme ultra-violet (EUV) estimated $\sim$$45.66^{+0.10}_{-0.33} \; \mathrm{erg} \, \mathrm{s^{-1}}$. A late-time X-ray flare was also observed, reaching an absorbed $1.67 \times 10^{43} \mathrm{s^{-1}}$ approximately 300 days...