A5050412720- Astrophysics and Cosmic Phenomena
- Gamma-ray bursts and supernovae
- Dark Matter and Cosmic Phenomena
- Radio Astronomy Observations and Technology
- Crystallization and Solubility Studies
- Advanced Radiotherapy Techniques
- X-ray Diffraction in Crystallography
- Radiation Therapy and Dosimetry
- Metal complexes synthesis and properties
- Particle Detector Development and Performance
- Nuclear Physics and Applications
- Neutrino Physics Research
- Crystal structures of chemical compounds
- Radiation Dose and Imaging
- Radiomics and Machine Learning in Medical Imaging
- Organometallic Complex Synthesis and Catalysis
- Advances in Oncology and Radiotherapy
- Organometallic Compounds Synthesis and Characterization
- Solar and Space Plasma Dynamics
- Pulsars and Gravitational Waves Research
- Telemedicine and Telehealth Implementation
- Particle Accelerators and Free-Electron Lasers
- Geophysics and Gravity Measurements
- Radiation Detection and Scintillator Technologies
- Synthesis and characterization of novel inorganic/organometallic compounds
McGill University
2015-2025
McGill University Health Centre
2016-2025
Detec (Norway)
2016
Canadian Nuclear Safety Commission
2014
Center for Astrophysics Harvard & Smithsonian
2007-2011
Montreal General Hospital
2010
Harvard University Press
2008-2009
National University of Ireland
2001-2008
University of Delaware
2008
Case Western Reserve University
2008
The accretion of matter onto a massive black hole is believed to feed the relativistic plasma jets found in many active galactic nuclei (AGN). Although some AGN accelerate particles energies exceeding 10^12 electron Volts (eV) and are bright sources very-high-energy (VHE) gamma-ray emission, it not yet known where VHE emission originates. Here we report on radio observations galaxy M87, revealing period extremely strong flares accompanied by increase flux from its nucleus. These results...
We report results from an intensive multiwavelength monitoring campaign on the TeV blazar Mrk 421 over period of 2003-2004. The source was observed simultaneously at energies with Whipple 10 m telescope and X-ray Rossi X-Ray Timing Explorer (RXTE) during each clear night within observing windows. Supporting observations were also frequently carried out optical radio wavelengths to provide simultaneous or contemporaneous coverages. large amount data has allowed us examine variability in...
We present a detailed analysis of week-long simultaneous observations the blazar Mrk 421 at 2-60 keV X-rays (RXTE) and TeV γ-rays (Whipple HEGRA) in 2001. Accompanying optical monitoring was performed with Mt. Hopkins 48 inch telescope. The unprecedented quality this data set enables us to establish existence correlation between X-ray luminosities, also start unveiling some its characteristics, particular energy dependence time variability. source shows strong variations both γ-ray bands,...
LS I +61 303 is one of only a few high-mass X-ray binaries currently detected at high significance in very energy gamma-rays. The system was observed over several orbital cycles (between September 2006 and February 2007) with the VERITAS array imaging air-Cherenkov telescopes. A signal gamma-rays energies above 300 GeV found statistical 8.4 standard deviations. flux measured to be strongly variable; maximum during most apastron. spectrum for period emission can characterized by power law...
We present evidence that the very high energy (VHE, E > 100 GeV) gamma-ray emission coincident with supernova remnant IC 443 is extended. contains one of best studied sites remnant/molecular cloud interaction and pulsar wind nebula CXOU J061705.3+222127, both which are important targets for VHE observations. VERITAS observed 37.9 hr during 2007 detected above 300 GeV an excess 247 events, resulting in a significance 8.3 standard deviations (σ) before trials 7.5σ after point-source search....
Patient portals are increasingly accepted as part of standard medical care. However, to date, most patient provide just passive access data. The use modern technology such smartphones and data personalization algorithms offers the potential make more person-centered enabling.The aim this study is share our experience in designing developing a portal following participatory stakeholder co-design approach.Our approach comprised 6 core elements: (1) equal coleadership, including cancer on...
We report a possible detection of TeV gamma-rays from the Galactic Center by Whipple 10m gamma-ray telescope. Twenty-six hours data were taken over an extended period 1995 through 2003 resulting in total significance 3.7 standard deviations. The measured excess corresponds to integral flux \Flux above energy $2.8 \mathrm{TeV}$, roughly 40% Crab Nebula at this energy. 95% confidence region has angular extent about 15 arcmin and includes position Sgr A*. is consistent with point source shows...
The multiwavelength observation of the nearby radio galaxy M87 provides a unique opportunity to study in detail processes occurring active galactic nuclei from waves TeV γ-rays. Here we report detection γ-ray emission above 250 GeV spring 2007 with VERITAS atmospheric Cerenkov telescope array and discuss its correlation X-ray emission. is measured be pointlike an intrinsic source radius less than 4.5'. differential energy spectrum fitted well by power-law function: dΦ/dE = (7.4 ± 1.3stat...
The intermediate-frequency peaked BL Lacertae (IBL) object 3C 66A is detected during 2007 - 2008 in VHE (very high energy: E > 100 GeV) gamma-rays with the VERITAS stereoscopic array of imaging atmospheric Cherenkov telescopes. An excess 1791 events detected, corresponding to a significance 21.2 standard deviations (sigma), these observations (32.8 hours live time). observed integral flux above 200 GeV 6% Crab Nebula's and shows evidence for variability on time-scale days. measured energy...
VERITAS, an Imaging Atmospheric Cherenkov Telescope (IACT) system for gammma‐ray astronomy in the GeV‐TeV range, has recently completed its first season of observations with a full array four telescopes. A number astrophysical gamma‐ray sources have been detected, both galactic and extragalactic, including previously unknown at TeV energies. We describe status some highlight results, assess technical performance, sensitivity shower reconstruction capabilities.
Since September 2005, the Whipple 10m Gamma-ray Telescope has been operated primarily as a blazar monitor. The five Northern Hemisphere blazars that have already detected at Observatory, Markarian 421, H1426+428, 501, 1ES 1959+650 and 2344+514, are monitored routinely each night they visible. We report on 421 observations taken from November 2005 to June 2006 in gamma-ray, X-ray, optical radio bands. During this time, was found be variable all wavelengths probed. Both variability...
We present the first strong detection of very high energy gamma-rays from close (z=0.048) X-ray selected BL Lacertae object 1ES1959+650. Observations were made with Whipple 10m telescope on Mt. Hopkins, Arizona, using atmospheric Cherenkov imaging technique. The flux between May and July 2002 was highly variable, a mean 0.64 +/- 0.03 times steady Crab Nebula reaching maximum five Crab, variability timescales as short seven hours.
A very high energy γ-ray signal has been detected at the 5.5 σ level from H1426+428, an X-ray-selected BL Lacertae object a redshift of 0.129. The was monitored 1995 to 1998 with Whipple 10 m imaging atmospheric Cerenkov telescope as part general blazar survey; results these observations, although not statistically significant, were consistently positive. X-ray observations H1426+428 during 1999 BeppoSAX instrument revealed that peak its synchrotron spectrum occurs greater than 100 keV,...
The detection of spectral variability the γ-ray blazar Mrk 421 at TeV energies is reported. Observations with Whipple Observatory 10 m telescope taken in 2000/2001 revealed exceptionally strong and long-lasting flaring activity. Flaring levels 0.4-13 times that Crab Nebula flux provided sufficient statistics for a detailed study energy spectrum between 380 GeV 8.2 as function level. These spectra are well described by power law an exponential cutoff: dN/dE ∝ E-αe m-2 s-1 TeV-1. There no...
The VERITAS collaboration reports the detection of very-high-energy gamma-ray emission from high-frequency-peaked BL Lac object 1ES 1218+304 located at a redshift z = 0.182. A signal was detected with statistical significance 10.4 standard deviations (10.4σ) for observations taken during first three months 2007, confirming discovery this made by MAGIC collaboration. photon spectrum between ∼160 GeV and ∼1.8 TeV is well described power law an index Γ 3.08 ± 0.34stat 0.2sys. integral flux...
We report on the results of two coordinated multiwavelength campaigns that focused blazar Markarian 421 during its 2006 and 2008 outbursts. These obtained UV X-ray data using XMM-Newton satellite, while gamma-ray were utilizing three imaging atmospheric Cerenkov telescopes, Whipple 10 m telescope VERITAS, both based in Arizona, as well MAGIC telescope, La Palma Canary Islands. The effort between groups allowed for truly simultaneous UV/X-ray/gamma-ray wavelengths a significant portion...
Purpose: Out‐of‐field neutron doses resulting from photonuclear interactions in the head of a linear accelerator pose an iatrogenic risk to patients and occupational personnel during radiotherapy. To quantify production, in‐room measurements have traditionally been carried out using Bonner sphere systems (BSS) with activation foils TLDs. In this work, recently developed active detector, nested spectrometer (NNS), was tested radiotherapy bunkers. Methods: The NNS is designed for easy handling...
Radiomics-based machine learning classifiers have shown potential for detecting bone metastases (BM) and evaluating BM response to radiotherapy (RT). However, current radiomics models require large datasets of images with expert-segmented 3D regions interest (ROIs). Full ROI segmentation is time consuming oncologists often outline just RT treatment fields in clinical practice. This presents a challenge real-world research. As such, method that simplifies identification but does not...
Objective: To build and validate a simulation framework to perform single-cell bulk-cell whole genome sequencing of radiation-exposed Monte Carlo cell models assist radiation genomics studies. Approach: Sequencing the genomes radiation-damaged cells can provide useful insight into action for radiobiology research. However, carrying out post-irradiation experiments often be challenging, expensive, time-consuming. Although computational simulations have potential solutions these experimental...
Abstract The reported relative biological effectiveness (RBE) for thermal neutrons has a large range (5–51, cytogenetic endpoints), which can confound radiation protection decision-making. To determine whether neutron spectra influence RBE, the RBE of reactor-derived average energy 31 meV was evaluated in human peripheral blood lymphocytes using two classical DNA double-strand break endpoints: dicentric chromosome assay (DCA) and cytokinesis-block micronucleus assay. Dose-response curves 41...
The BL Lac object H1426+428 was recently detected as a high energy gamma-ray source by the VERITAS collaboration (Horan et al. 2002). We have reanalyzed 2001 portion of data used in detection order to examine spectrum above 250 GeV. find that time-averaged agrees with power law shape dF/dE = 10^(-7.31 +- 0.15(stat) 0.16(syst)) x E^(-3.50 0.35(stat) 0.05(syst)) m^(-2)s^(-1)TeV^(-1) statistical evidence from our for emission 2.5 TeV is 2.6 sigma. With 95% c.l., integral flux larger than 3%...