Masoud Rafiei-Ravandi
A5064620376- Pulsars and Gravitational Waves Research
- Gamma-ray bursts and supernovae
- Astrophysical Phenomena and Observations
- GNSS positioning and interference
- earthquake and tectonic studies
- Radio Astronomy Observations and Technology
- Astrophysics and Cosmic Phenomena
- Galaxies: Formation, Evolution, Phenomena
- Geophysics and Gravity Measurements
- Astronomy and Astrophysical Research
- Cosmology and Gravitation Theories
- Statistical and numerical algorithms
- Seismology and Earthquake Studies
- Ionosphere and magnetosphere dynamics
- Geophysics and Sensor Technology
- Atomic and Subatomic Physics Research
- Earthquake Detection and Analysis
- Solar and Space Plasma Dynamics
- Structural Analysis and Optimization
- Seismic and Structural Analysis of Tall Buildings
- Seismic Imaging and Inversion Techniques
- Magnetic confinement fusion research
- Non-Invasive Vital Sign Monitoring
- Inertial Sensor and Navigation
- Stellar, planetary, and galactic studies
McGill University
2022-2025
Perimeter Institute
2019-2023
University of Waterloo
2021-2023
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...
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...
Abstract We report on the discovery and analysis of bursts from nine new repeating fast radio burst (FRB) sources found using Canadian Hydrogen Intensity Mapping Experiment (CHIME) telescope. These span a dispersion measure (DM) range 195–1380 pc cm −3 . detect two three sources, four one source, five source. determine sky coordinates all with uncertainties ∼10′. Faraday rotation measures (RMs) for values −20(1) −499.8(7) rad m −2 , that are substantially lower than RM derived emitted by FRB...
We report on the discovery of FRB 20200120E, a repeating fast radio burst (FRB) with low dispersion measure (DM), detected by Canadian Hydrogen Intensity Mapping Experiment (CHIME)/FRB project. The source DM 87.82 pc cm$^{-3}$ is lowest recorded from an to date, yet significantly higher than maximum expected Milky Way interstellar medium in this direction (~ 50 cm$^{-3}$). have three bursts and one candidate over period 2020 January-November. baseband voltage data for event January 20...
Abstract We present a synthesis of fast radio burst (FRB) morphology (the change in flux as function time and frequency) detected the 400–800 MHz octave by FRB project on Canadian Hydrogen Intensity Mapping Experiment (CHIME/FRB), using events from first CHIME/FRB catalog. The catalog consists 62 bursts 18 repeating sources, plus 474 one-off FRBs, between 2018 July 25 2019 2. identify four observed archetypes (“simple broadband,” “simple narrowband,” “temporally complex,” “downward...
We present the discovery of 25 new repeating fast radio burst (FRB) sources found among CHIME/FRB events detected between 2019 September 30 and 2021 May 1. The were using a clustering algorithm that looks for multiple co-located on sky having similar dispersion measures (DMs). repeaters have DMs ranging from $\sim$220 pc cm$^{-3}$ to $\sim$1700 cm$^{-3}$, include exhibited as few two bursts many twelve. report statistically significant difference in both DM extragalactic (eDM) distributions...
Abstract Fast radio bursts (FRBs) are brief, energetic, typically extragalactic flashes of emission whose progenitors largely unknown. Although studying the FRB population is essential for understanding how these astrophysical phenomena occur, such studies have been difficult to conduct without large numbers FRBs and characterizable observational biases. Using recently released catalog 536 published by Canadian Hydrogen Intensity Mapping Experiment/Fast Radio Burst (CHIME/FRB) collaboration,...
Abstract We present a search for host galaxy associations the third set of repeating fast radio burst (FRB) sources discovered by CHIME/FRB Collaboration. Using ∼1′ baseband localizations and probabilistic methods, we identify potential galaxies two FRBs, 20200223B 20190110C at redshifts 0.06024(2) 0.12244(6), respectively. also discuss properties marginal candidate association FRB 20191106C with redshift 0.10775(1). The three putative are all relatively massive, fall on standard...
Abstract We present the host galaxies of four apparently nonrepeating fast radio bursts (FRBs), FRB 20181223C, 20190418A, 20191220A, and 20190425A, reported in first Canadian Hydrogen Intensity Mapping Experiment (CHIME/FRB) catalog. Our selection these FRBs is based on a planned hypothesis testing framework where we search all CHIME/FRB Catalog-1 events that have low extragalactic dispersion measure (<100 pc cm −3 ), with high Galactic latitude (∣ b ∣ > 10°) saved baseband data....
Abstract In 2021, a catalog of 536 fast radio bursts (FRBs) detected with the Canadian Hydrogen Intensity Mapping Experiment (CHIME) telescope was released by CHIME/FRB Collaboration. This large collection bursts, observed single instrument and uniform selection effects, has advanced our understanding FRB population. Here we update results for 140 these FRBs which channelized raw voltage (“baseband”) data are available. With voltages measured telescope’s antennas, it is possible to maximize...
Abstract We report the discovery of repeating fast radio burst (FRB) source FRB 20240209A using Canadian Hydrogen Intensity Mapping Experiment (CHIME)/FRB telescope. detected 22 bursts from this repeater between 2024 February and July, 6 which were also recorded at Outrigger station k’niʔatn k’l ⌣ stk’masqt (KKO). The multiple very long baseline interferometry localizations 66 km CHIME–KKO baseline, each with a different vector orientation due to repeater’s high decl. ∼86°, enabled combined...
Abstract The discovery and localization of FRB 20240209A by the Canadian Hydrogen Intensity Mapping Fast Radio Burst (CHIME/FRB) experiment marks first repeating localized with CHIME/FRB Outriggers adds to small sample FRBs associated host galaxies. Here we present Keck Gemini observations that reveal a redshift z = 0.1384 ± 0.0004. We perform stellar population modeling jointly fit optical through mid-IR data infer median mass log( M * / ⊙ ) 11.35 0.01 mass-weighted age ~11 Gyr,...
Abstract We present a spectro-temporal analysis of 137 fast radio bursts (FRBs) from the first CHIME/FRB baseband catalog, including 125 one-off and 12 repeat bursts, down to microsecond resolution using least-squares optimization fitting routine fitburst . measure subburst components within burst envelopes as narrow ~23 μ s (FWHM), with 20% sample displaying substructures narrower than 100 s, offering constraints on emission mechanisms. Scattering timescales in range 30 13 ms at 600 MHz....
Abstract We report on the detection of seven bursts from periodically active, repeating fast radio burst (FRB) source FRB 180916.J0158+65 in 300–400 MHz frequency range with Green Bank Telescope (GBT). Emission multiple is visible down to bottom GBT band, suggesting that cutoff (if it exists) for emission lower than 300 MHz. Observations were conducted during predicted periods activity source, and had simultaneous coverage Low Frequency Array (LOFAR) backend Canadian Hydrogen Intensity...
Abstract The repeating FRB 20201124A was first discovered by CHIME/FRB in November of 2020, after which it seen to repeat a few times over several months. It entered period high activity April 2021, at time observatories recorded tens hundreds more bursts from the source. These follow-up observations enabled precise localization and host-galaxy identification. In this paper, we report on CHIME/FRB-detected 20201124A, including their best-fit morphologies, fluences, arrival times. large...
Fast radio burst (FRB) source 20180916B exhibits a 16.33-day periodicity in its activity. It is as of yet unclear what proposed mechanism produces the activity, but polarization information key diagnostic. Here, we report on properties 44 bursts from FRB detected between 2018 December and 2021 by CHIME/FRB, project Canadian Hydrogen Intensity Mapping Experiment Experiment. In contrast to previous observations, find significant variations Faraday rotation measure (RM) 20180916B. Over nine...
We report on improved sky localizations of thirteen repeating fast radio bursts (FRBs) discovered by CHIME/FRB via the use interferometric techniques channelized voltages from telescope. These so-called 'baseband localizations' improve localization uncertainty area presented in past studies more than three orders magnitude. The regions are provided for full sample FRBs to enable follow-up studies. uncertainties, together with limits source distances their dispersion measures (DMs), allow us...
Abstract Fast radio bursts (FRBs) display a confounding variety of burst properties and host-galaxy associations. Repeating FRBs offer insight into the FRB population by enabling spectral, temporal, polarimetric to be tracked over time. Here, we report on polarized observations 12 repeating sources using multiyear monitoring with Canadian Hydrogen Intensity Mapping Experiment (CHIME) 400–800 MHz. We observe significant rotation measure (RM) variations from many in our sample, including RM...
Abstract Localizing fast radio bursts (FRBs) to their host galaxies is an essential step better understanding origins and using them as cosmic probes. The Canadian Hydrogen Intensity Mapping Experiment (CHIME)/FRB Outriggers program aims add very long baseline interferometry localization capabilities CHIME, such that FRBs may be localized tens of milliarcsecond precision at the time discovery, more than sufficient for galaxy identification. first-built outrigger telescope Outrigger (KKO),...