Emmanuel Fonseca
A5087315310- Pulsars and Gravitational Waves Research
- Gamma-ray bursts and supernovae
- Geophysics and Gravity Measurements
- Radio Astronomy Observations and Technology
- Astrophysical Phenomena and Observations
- Cosmology and Gravitation Theories
- GNSS positioning and interference
- Advanced Frequency and Time Standards
- Astrophysics and Cosmic Phenomena
- Galaxies: Formation, Evolution, Phenomena
- Stellar, planetary, and galactic studies
- Solar and Space Plasma Dynamics
- earthquake and tectonic studies
- Astronomical Observations and Instrumentation
- High-pressure geophysics and materials
- Atomic and Subatomic Physics Research
- Statistical and numerical algorithms
- Geophysics and Sensor Technology
- Black Holes and Theoretical Physics
- Astronomy and Astrophysical Research
- Inertial Sensor and Navigation
- Superconducting Materials and Applications
- Ionosphere and magnetosphere dynamics
- Superconducting and THz Device Technology
- Particle Accelerators and Free-Electron Lasers
West Virginia University
2021-2025
McGill University
2017-2023
Morgantown High School
2023
Campbell Collaboration
2023
University of British Columbia
2014-2018
Universidade Federal de Santa Catarina
2013-2014
Pennsylvania State University
2010-2013
Goddard Space Flight Center
2010-2013
Universities Space Research Association
2013
Deleted Institution
2010
PSR J0740$+$6620 has a gravitational mass of $2.08\pm 0.07~M_\odot$, which is the highest reliably determined any neutron star. As result, measurement its radius will provide unique insight into properties star core matter at high densities. Here we report based on fits rotating hot spot patterns to Neutron Star Interior Composition Explorer (NICER) and X-ray Multi-Mirror (XMM-Newton) observations. We find that equatorial circumferential $13.7^{+2.6}_{-1.5}$ km (68%). apply our measurement,...
Abstract We report on Bayesian estimation of the radius, mass, and hot surface regions massive millisecond pulsar PSR J0740+6620, conditional pulse-profile modeling Neutron Star Interior Composition Explorer X-ray Timing Instrument event data. condition informative distance, orbital inclination priors derived from joint North American Nanohertz Observatory for Gravitational Waves Canadian Hydrogen Intensity Mapping Experiment/Pulsar wideband radio timing measurements Fonseca et al. use...
Abstract We report multiple lines of evidence for a stochastic signal that is correlated among 67 pulsars from the 15 yr pulsar timing data set collected by North American Nanohertz Observatory Gravitational Waves. The correlations follow Hellings–Downs pattern expected gravitational-wave background. presence such background with power-law spectrum favored over model only independent noises Bayes factor in excess 10 14 , and this same an uncorrelated common factors 200–1000, depending on...
Abstract We present high-precision timing data over time spans of up to 11 years for 45 millisecond pulsars observed as part the North American Nanohertz Observatory Gravitational Waves (NANOGrav) project, aimed at detecting and characterizing low-frequency gravitational waves. The were with Arecibo and/or Green Bank Telescope frequencies ranging from 327 MHz 2.3 GHz. Most approximately monthly cadence, six high-timing-precision weekly. All widely separated each observing epoch in order fit...
Abstract The 15 yr pulsar timing data set collected by the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) shows positive evidence presence of a low-frequency gravitational-wave (GW) background. In this paper, we investigate potential cosmological interpretations signal, specifically cosmic inflation, scalar-induced GWs, first-order phase transitions, strings, and domain walls. We find that, with exception stable strings field theory origin, all these models can...
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...
The highly stable spin of neutron stars can be exploited for a variety (astro)physical investigations. In particular, arrays pulsars with rotational periods the order milliseconds used to detect correlated signals such as those caused by gravitational waves. Three ‘pulsar timing arrays’ (PTAs) have been set up around world over past decades and collectively form ‘International’ PTA (IPTA). this paper, we describe first joint analysis data from three regional PTAs, i.e. IPTA set. We available...
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 We analyze 24 binary radio pulsars in the North American Nanohertz Observatory for Gravitational Waves (NANOGrav) nine-year data set. make 14 significant measurements of Shapiro delay, including new detections four pulsar-binary systems (PSRs J0613−0200, J2017+0603, J2302+4442, and J2317+1439), derive estimates binary-component masses orbital inclination these MSP-binary systems. find a wide range pulsar masses, with values as low <?CDATA...
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...
We compute upper limits on the nanohertz-frequency isotropic stochastic gravitational wave background (GWB) using 9-year data release from North American Nanohertz Observatory for Gravitational Waves (NANOGrav) collaboration. set a GWB supermassive black hole binaries under power law, broken and free spectral coefficient GW spectrum models. place 95\% limit strain amplitude (at frequency of yr$^{-1}$) in law model $A_{\rm gw} < 1.5\times 10^{-15}$. For model, we priors derived simulations...
We searched for an isotropic stochastic gravitational wave background in the second data release of International Pulsar Timing Array, a global collaboration synthesizing decadal-length pulsar-timing campaigns North America, Europe, and Australia. In our reference search power law strain spectrum form $h_c = A(f/1\,\mathrm{yr}^{-1})^{\alpha}$, we found strong evidence spectrally-similar low-frequency process amplitude $A 3.8^{+6.3}_{-2.5}\times10^{-15}$ spectral index $\alpha -0.5 \pm 0.5$,...
In this paper, we describe the International Pulsar Timing Array second data release, which includes recent pulsar timing obtained by three regional consortia: European Array, North American Nanohertz Observatory for Gravitational Waves, and Parkes Array. We analyse where possible combine high-precision 65 millisecond pulsars are regularly observed these groups. A basic noise analysis, including processes both correlated uncorrelated in time, provides models ephemerides pulsars. find that...
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...
The NANOGrav 15-year data set shows evidence for the presence of a low-frequency gravitational-wave background (GWB). While many physical processes can source such gravitational waves, here we analyze signal as coming from population supermassive black hole (SMBH) binaries distributed throughout Universe. We show that astrophysically motivated models SMBH binary populations are able to reproduce both amplitude and shape observed spectrum. multiple model variations GWB spectrum at our current...
We present high-precision timing observations spanning up to nine years for 37 millisecond pulsars monitored with the Green Bank and Arecibo radio telescopes as part of North American Nanohertz Observatory Gravitational Waves (NANOGrav) project. describe observational instrumental setups used collect data, methodology applied calculating pulse times arrival; these include novel methods measuring offsets characterizing low signal-to-noise ratio results. The time arrival data are fit a...
Abstract We present observations and timing analyses of 68 millisecond pulsars (MSPs) comprising the 15 yr data set North American Nanohertz Observatory for Gravitational Waves (NANOGrav). NANOGrav is a pulsar array (PTA) experiment that sensitive to low-frequency gravitational waves (GWs). This NANOGrav’s fifth public release, including both “narrowband” “wideband” time-of-arrival (TOA) measurements corresponding models. have added 21 MSPs extended our baselines by 3 yr, now spanning nearly...
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 search for an isotropic stochastic gravitational-wave background (GWB) in the 12.5 yr pulsar-timing data set collected by North American Nanohertz Observatory Gravitational Waves. Our analysis finds strong evidence of a process, modeled as power law, with common amplitude and spectral slope across pulsars. Under our fiducial model, Bayesian posterior f −2/3 power-law spectrum, expressed characteristic GW strain, has median 1.92 × 10 −15 5%–95% quantiles 1.37–2.67 at reference...