A5065908595- Pulsars and Gravitational Waves Research
- Nuclear physics research studies
- Gamma-ray bursts and supernovae
- Nuclear Physics and Applications
- Geophysics and Gravity Measurements
- Astrophysics and Cosmic Phenomena
- High-pressure geophysics and materials
- Astrophysical Phenomena and Observations
- Atomic and Molecular Physics
- Astronomical and nuclear sciences
- Superconducting Materials and Applications
- Nuclear reactor physics and engineering
- Quantum Chromodynamics and Particle Interactions
- Atomic and Subatomic Physics Research
- High-Energy Particle Collisions Research
- Radio Astronomy Observations and Technology
- Particle Accelerators and Free-Electron Lasers
- Dark Matter and Cosmic Phenomena
- Particle physics theoretical and experimental studies
- Cosmology and Gravitation Theories
- Plant Pathogens and Fungal Diseases
- Astro and Planetary Science
- Scientific Research and Discoveries
- Laser-induced spectroscopy and plasma
- Geological and Geochemical Analysis
Hope College
2007-2020
University of Turin
2002-2020
Goddard Space Flight Center
2005-2020
Rice University
2020
Los Alamos National Laboratory
2020
Universities Space Research Association
2020
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2005-2011
CEA Paris-Saclay
2005-2011
Astrophysique, Instrumentation et Modélisation
2011
Université Paris Cité
2005-2011
Magnetic photon splitting γ → γγ, a quantum electrodynamics process that becomes important only in magnetic fields approaching the critical value, Bcr = 4.41 × 1013 G, is investigated as mechanism for attenuation of γ-rays emitted near surface strongly magnetized pulsars. Since has no threshold, it can attenuate photons and degrade their energies below threshold one-photon pair production, high enough may dominate above threshold. We model photon-splitting subsequent cascades γ-ray pulsars,...
We present results of a population synthesis millisecond pulsars from the Galactic disk.Excluding globular clusters, we model spatial distribution by assuming their birth in disk with random kick velocity and evolve them to within potential.We assume that normal are standard candles described common radio luminosity invokes new relationship between core cone emission suggested recent studies.In modeling beams, explore relativistic effects time delay, aberration sweepback open field...
The multifragment emission of ``completely characterized'' events in the $^{40}\mathrm{Ca}$${+}^{40}$Ca system at 35 MeV/nucleon has been compared to predictions several models. observed is not agreement with models based on conventional statistical binary decay, but both a simultaneous multifragmentation model and sequential which expansion treated.
Hard, non-thermal, persistent pulsed X-ray emission extending between 10 keV and $\sim 150$ has been observed in nearly ten magnetars. For inner-magnetospheric models of such emission, resonant inverse Compton scattering soft thermal photons by ultra-relativistic charges is the most efficient production mechanism. We present angle-dependent upscattering spectra intensity maps for uncooled, relativistic electrons injected inner regions magnetar magnetospheres, calculated using collisional...
We present results of a pulsar population synthesis study that incorporates number recent developments and some significant improvements over our previous study. have included the Parkes multibeam survey in select group nine radio surveys, doubling sample pulsars. More realistic geometries for γ-ray beams are Monte Carlo computer code, which simulates characteristics Galactic adopted with modifications radio-beam geometry Arzoumanian, Chernoff, Cordes. For beam, we assumed slot gap described...
Light charged-particle emission and neutron have been measured for the fusion-evaporation fusion-fission channels in $^{60}\mathrm{Ni}$${+}^{100}$Mo reaction at 550 655 MeV bombarding energies. Temperatures, barriers, multiplicities particles detected coincidence with evaporation residues fission fragments determined. For residue data, ``first-chance'' spectra of emitted from compound nucleus isolated same initial temperature different evaporated has extracted. The inverse level density...
Observations by the Fermi Large Area Telescope of gamma-ray millisecond pulsar light curves imply copious pair production in their magnetospheres, and not exclusively those younger pulsars. Such cascades may be a primary source Galactic electrons positrons, contributing to observed enhancement positron flux above ~10 GeV. has also uncovered many new pulsars, impacting stellar population models. We investigate contribution pulsars terrestrial cosmic-ray positrons. Our synthesis code predicts...
In more than four years of observation the Large Area Telescope on board Fermi satellite has identified pulsed $\gamma$-ray emission from 80 young pulsars, providing light curves with high statistics. Fitting observations geometrical models can provide estimates magnetic obliquity $\alpha$ and aspect angle $\zeta$, yielding radiation beaming factor luminosity. Using geometries (Polar Cap, Slot Gap, Outer One Pole Caustic) radio geometry, we fit for 76 pulsars jointly their plus when...
We simulate the characteristics of Galactic population radio and $\gamma$-ray pulsars using Monte Carlo techniques. At birth, neutron stars are spatially distributed in disk, with supernova-kick velocities, randomly dispersed age back to $10^9$ years. They evolved gravitational potential present time. From a luminosity model, flux is filtered through selected set radio-survey parameters. luminosities assigned features recent polar cap acceleration models invoking space-charge-limited flow,...
Gnomoniopsis castanea is an emerging fungal pathogen causing nut rot of sweet chestnut, Castanea sativa . This study was aimed at testing and modelling the effects climate on disease incidence. Up to 120 ripe nuts were collected in 2011 from trees each 12 sites located northwest Italy. The incidence G site expressed as number infected out total sampled (%), determined by combining results morphological identification isolates obtained nuts, their typing through a newly developed...
Abstract We present the results of a population synthesis radio and γ -ray millisecond pulsars (MSPs) from galactic disk (GD). Using 92 MSPs detected in 13 surveys 54 Fermi as point sources first source catalog, we establish six free parameters corresponding to overall factor exponents period derivative dependence for each empirical luminosity models. test three high-energy emission models described by two-pole caustic slot-gap, outer-gap, pair-starved polar-cap geometries. The simulated...
ABSTRACT Nearly one-third of the sources listed in Third Fermi Large Area Telescope (LAT) catalog (3FGL) remain unassociated. It is possible that predicted and even unanticipated gamma-ray source classes are present these data waiting to be discovered. Taking advantage excellent spectral capabilities achieved by LAT, we use machine-learning classifiers (Random Forest XGBoost) pinpoint potentially novel unassociated 3FGL sample outside Galactic plane. Here report a total 34 high-confidence...
Hybridization between species is being recognized as a major force in the rapid adaptive evolution of fungal plant pathogens. The first stages interspecific hybridization necessarily involve nuclear-mitochondrial chimeras. In their 2001 publication, Olson and Stenlid reported that mitochondria control virulence generation hybrids North American pathogen Heterobasidion irregulare its congeneric H. occidentale. By assessing saprobic ability gene expression × annosum sensu stricto parental...
The recent ALADIN report of limiting temperatures for nuclear disassembly, derived from measurements isotopic ratios He and Li nuclei, is discussed. It suggested that the entire excitation energy dependence which observed may result fact onset Coulomb instability are being measured progressively lighter neutron rich nuclei as per nucleon increases. While basic observation plateauing in intermediate range remains valid, higher results not signal entry into vapor phase....
$\ensuremath{\gamma}$- ray multiplicities $〈{M}_{\ensuremath{\gamma}}〉$ and energies $〈{E}_{\ensuremath{\gamma}}〉$ associated with identified products of completely damped collisions 237-MeV $^{40}\mathrm{Ar}$ $^{89}\mathrm{Y}$ are analyzed to determine the angular momenta primary heavy fragments. Extending analysis system 175-MeV $^{20}\mathrm{Ne}$+Ag allows a comparison which indicates that different partial waves contribute in these two nearly identical composite systems at almost same...
With the large sample of young gamma-ray pulsars discovered by Fermi Large Area Telescope (LAT), population synthesis has become a powerful tool for comparing their collective properties with model predictions. We synthesised pulsar based on radio emission and four gap models (Polar Cap, Slot Gap, Outer One Pole Caustic) normalizing to number detected in select group surveys. The luminosity wide beams from outer gaps can easily account detections 2 years observations. slot-gap requires an...
This paper explores the effects of strong magnetic fields on Compton scattering relativistic electrons. Recent studies upscattering and energy loss by electrons that have used nonrelativistic, Thomson cross section for resonant or Klein-Nishina nonresonant do not account quantum (>4 × 1012 G). We derived a simplified expression exact QED broadly applicable case in which move along field. To facilitate applications to astrophysical models, we also developed compact approximate expressions...
The 4\ensuremath{\pi} multidetector AMPHORA has been used to measure yield distributions and energy spectra for products of the collisions in reactions $^{40}\mathrm{Ca}$ with at 35 MeV/nucleon. Events high multiplicity (\ensuremath{\ge}10) which \ensuremath{\ge}85% total entrance channel atomic number is detected have isolated found result from most violent lead excitation energies near 6 A large fraction these multifragment final states. detailed comparison experimental data results...
Cyclotron decay and absorption rates have been well studied in the literature, focusing primarily on spectral, angular polarization dependence. Astrophysical applications usually do not require retention of information electron spin state, these are normally averaged obtaining requisite rates. In magnetic fields, higher order quantum processes such as Compton scattering become resonant at cyclotron frequency its harmonics, with resonances being formally divergent. Such divergences eliminated...