V. M. Kaspi
A5040720897- Pulsars and Gravitational Waves Research
- Astrophysical Phenomena and Observations
- Gamma-ray bursts and supernovae
- Geophysics and Gravity Measurements
- High-pressure geophysics and materials
- Radio Astronomy Observations and Technology
- Astrophysics and Cosmic Phenomena
- Superconducting Materials and Applications
- Astronomical Observations and Instrumentation
- Stellar, planetary, and galactic studies
- GNSS positioning and interference
- Geophysics and Sensor Technology
- Astronomy and Astrophysical Research
- Advanced Frequency and Time Standards
- Particle Accelerators and Free-Electron Lasers
- Cosmology and Gravitation Theories
- Earthquake Detection and Analysis
- earthquake and tectonic studies
- Magnetic confinement fusion research
- Solar and Space Plasma Dynamics
- Particle Detector Development and Performance
- Statistical and numerical algorithms
- Astro and Planetary Science
- Seismology and Earthquake Studies
- Nuclear Physics and Applications
McGill University
2016-2025
Space Science Institute
2023
California Institute of Technology
1994-2018
Goddard Space Flight Center
2008-2018
Canadian Institute for Advanced Research
2008-2017
Université de Montréal
2015
Max Planck Institute for Radio Astronomy
2014-2015
Max Planck Society
2014-2015
Research Canada
2003-2014
West Virginia University
2008-2011
Many physically motivated extensions to general relativity (GR) predict substantial deviations in the properties of spacetime surrounding massive neutron stars. We report measurement a 2.01 ± 0.04 solar mass (M⊙) pulsar 2.46-hour orbit with 0.172 0.003 M⊙ white dwarf. The high and compact make this system sensitive laboratory previously untested strong-field gravity regime. Thus far, observed orbital decay agrees GR, supporting its validity even for extreme conditions present system....
The Nuclear Spectroscopic Telescope Array (NuSTAR) mission, launched on 2012 June 13, is the first focusing high-energy X-ray telescope in orbit. NuSTAR operates band from 3 to 79 keV, extending sensitivity of far beyond ∼10 keV cutoff achieved by all previous satellites. inherently low background associated with concentrating light enables probe hard sky a more than 100-fold improvement over collimated or coded mask instruments that have operated this bandpass. Using its unprecedented...
We have discovered a 716-hertz eclipsing binary radio pulsar in the globular cluster Terzan 5 using Green Bank Telescope. It is fastest spinning neutron star found to date, breaking 24-year record held by 642-hertz B1937+21. The difficulty detecting this pulsar, because of its very low flux density and high eclipse fraction (approximately 40% orbit), suggests that even faster stars exist. If has mass less than twice Sun, then radius must be constrained spin rate <16 kilometers. short period...
We present a catalog of the 26 currently known magnetars and magnetar candidates. tabulate astrometric timing data for all sources, as well their observed radiative properties, particularly spectral parameters quiescent X-ray emission. show histograms spatial properties magnetars, comparing them with pulsar population, we investigate plot possible correlations between timing, X-ray, multiwavelength properties. find scale height to be in range 20–31 pc, assuming they are exponentially...
Magnetars are young and highly magnetized neutron stars which display a wide array of X-ray activity including short bursts, large outbursts, giant flares quasi-periodic oscillations, often coupled with interesting timing behavior enhanced spin-down, glitches anti-glitches. The bulk this is explained by the evolution decay an ultrastrong magnetic field, stressing breaking star crust, in turn drives twists external magnetosphere powerful magnetospheric currents. population detected magnetars...
The International Pulsar Timing Array project combines observations of pulsars from both northern and southern hemisphere observatories with the main aim detecting ultra-low frequency (∼ 10−9–10−8 Hz) gravitational waves. Here we introduce project, review methods used to search for waves emitted coalescing supermassive binary black-hole systems in centres merging galaxies discuss status project.
The precise localization of the repeating fast radio burst (FRB 121102) has provided first unambiguous association (chance coincidence probability $p\lesssim3\times10^{-4}$) an FRB with optical and persistent counterpart. We report on imaging spectroscopy counterpart find that it is extended ($0.6^{\prime\prime}-0.8^{\prime\prime}$) object displaying prominent Balmer [OIII] emission lines. Based spectrum line ratios, we classify as a low-metallicity, star-forming, $m_{r^\prime} = 25.1$ AB...
The Parkes multi-beam pulsar survey is a sensitive of strip along the Galactic plane with and to . It uses 13-beam receiver on 64-m radio telescope, receiving two polarizations per beam over 288-MHz bandwidth centred 1374 MHz. data acquisition systems are described in some detail. For periods range dispersion measures less than 300 cm−3 pc, nominal limiting flux density about 0.2 mJy. At shorter or longer higher dispersions, sensitivity reduced. Timing observations carried out for pulsars...
view Abstract Citations (570) References (62) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS High-Precision Timing of Millisecond Pulsars. III. Long-Term Monitoring PSRs B1855+09 and B1937+21 Kaspi, V. M. ; Taylor, J. H. Ryba, F. Biweekly timing observations have been made at the Arecibo Observatory for more than 7 8 year, respectively, with uniform procedures only a few modest gaps. On each observing date we measure an equivalent pulse arrival time PSR 1.4...
Radio pulsars with millisecond spin periods are thought to have been spun up by transfer of matter and angular momentum from a low-mass companion star during an X-ray-emitting phase. The the neutron stars in several such X-ray binary (LMXB) systems shown be regime, but no radio pulsations detected. Here we report on detection follow-up observations nearby pulsar (MSP) circular orbit optically identified star. Optical indicate that accretion disk was present this system within last decade....
We investigate the birth and evolution of Galactic isolated radio pulsars. begin by estimating their space velocity distribution from proper motion measurements Brisken et al. (2002, 2003). find no evidence for multimodality favor one in which absolute one-dimensional components are exponentially distributed with a three-dimensional mean 380^{+40}_{-60} km s^-1. then proceed Monte Carlo-based population synthesis, modelling properties pulsars, time evolution, detection Parkes Swinburne...
Recent work has exploited pulsar survey data to identify temporally isolated, millisecond-duration radio bursts with large dispersion measures (DMs). These have been interpreted as arising from a population of extragalactic sources, in which case they would provide unprecedented opportunities for probing the intergalactic medium; may also be linked new source classes. Until now, however, all so-called fast (FRBs) detected Parkes telescope and its 13-beam receiver, casting some concern about...
The dramatic increase in the number of known gamma-ray pulsars since launch Fermi Gamma-ray Space Telescope (formerly GLAST) offers first opportunity to study a sizable population these high-energy objects. This catalog summarizes 46 high-confidence pulsed detections using six months data taken by Large Area (LAT), Fermi's main instrument. Sixteen previously unknown were discovered searching for signals at positions bright sources seen with LAT, or objects suspected be neutron stars based on...
We search for an isotropic stochastic gravitational-wave background (GWB) in the newly released $11$-year dataset from North American Nanohertz Observatory Gravitational Waves (NANOGrav). While we find no significant evidence a GWB, place constraints on GWB population of supermassive black-hole binaries, cosmic strings, and primordial GWB. For first time, that upper limits detection statistics are sensitive to Solar System ephemeris (SSE) model used, SSE errors can mimic signal. developed...
We report on the discovery of eight repeating fast radio burst (FRB) sources found using Canadian Hydrogen Intensity Mapping Experiment (CHIME) telescope. These span a dispersion measure (DM) range 103.5 to 1281 pc cm$^{-3}$. They display varying degrees activity: six were detected twice, another three times, and one ten times. FRBs likely represent bright and/or high-rate end distribution infrequently sources. For all sources, we determine sky coordinates with uncertainties...
Abstract The millisecond-duration radio flashes known as fast bursts (FRBs) represent an enigmatic astrophysical phenomenon. Recently, the sub-arcsecond localization (∼100 mas precision) of FRB 121102 using Very Large Array has led to its unambiguous association with persistent and optical counterparts, identification host galaxy. However, even more precise is needed in order probe direct physical relationship between millisecond themselves associated emission. Here, we report...
We present a catalog of 536 fast radio bursts (FRBs) detected by the Canadian Hydrogen Intensity Mapping Experiment Fast Radio Burst (CHIME/FRB) Project between 400 and 800 MHz from 2018 July 25 to 2019 1, including 62 18 previously reported repeating sources. The represents first large sample, repeaters non-repeaters, observed in single survey with uniform selection effects. This facilitates comparative absolute studies FRB population. show that apparent non-repeaters have sky locations...