A5018349920- Gamma-ray bursts and supernovae
- Astrophysics and Cosmic Phenomena
- Pulsars and Gravitational Waves Research
- Astrophysical Phenomena and Observations
- Astro and Planetary Science
- Stellar, planetary, and galactic studies
- Solar and Space Plasma Dynamics
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Neutrino Physics Research
- Geophysics and Gravity Measurements
- Galaxies: Formation, Evolution, Phenomena
- History and Developments in Astronomy
- Cosmology and Gravitation Theories
- Radio Astronomy Observations and Technology
- Astronomical Observations and Instrumentation
- Ionosphere and magnetosphere dynamics
- Planetary Science and Exploration
- Dark Matter and Cosmic Phenomena
- Nuclear Physics and Applications
- High-pressure geophysics and materials
- Laser-Matter Interactions and Applications
- Spectroscopy and Laser Applications
- Advanced Fiber Laser Technologies
- Photorefractive and Nonlinear Optics
University of Virginia
2015-2024
McCormick (United States)
1981-2024
Électricité de France (France)
2018
National Institutes of Natural Sciences
2018
National Astronomical Observatory of Japan
2018
Lomonosov Moscow State University
2018
System Simulation (United Kingdom)
2010
United States Coast Guard
2009
European Southern Observatory
2007
University of Oxford
2007
view Abstract Citations (835) References (15) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Self-similar solutions for the interaction of stellar ejecta with an external medium. Chevalier, R. A. The a uniformly expanding gas stationary ambient medium is studied in case where matter has power-law density profile (ρ ∝ r-n), as well r-s). structure region can be found provided that s<3 and n>5. Models Type I supernovae indicate ρ r-7 may occur outer part star....
view Abstract Citations (566) References (36) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The radio and X-ray emission from type II supernovae. Chevalier, R. A. interaction of the outer parts a supernova envelope with circumstellar matter creates high-energy density shell. equation motion shell is deduced on basis approximations that thin profile power law in radius. It noted structure Rayleigh-Taylor unstable energy created by instability can be...
Beginning with the γ-ray bursts GRB 970228 and 970508, a standard model for interpretation of gamma-ray burst (GRB) afterglows emerged involving synchrotron emission from constant-energy blast wave expanding into constant-density, "interstellar" medium. However, massive star origin GRBs implies stellar wind environment, probably Wolf-Rayet star, we have previously suggested interaction models 980326, 980519, 980425/SN 1998bw. Here, extend theory in winds, considering strong cooling phases,...
view Abstract Citations (443) References (63) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Emission from Circumstellar Interaction in Normal Type II Supernovae Chevalier, Roger A. ; Fransson, Claes Most supernovae probably have red supergiant progenitor stars which are expected to slow, dense winds; multiwavelength observations of some show evidence for interaction the supernova with wind. Recent optical spectroscopy normal at ages ~10 yr or more has shown...
The radio emission from supernovae has been modeled as synchrotron the interaction between supernova and a presupernova stellar wind. shows late power-law decline early rise due to low-frequency absorption process, which, in some cases (SN 1979C SN 1980K), is well free-free by external However, flux rises many (e.g., 1987A Type Ib Ic supernovae) have not sufficiently observed define mechanism. assumption of self-absorption yields an approximate radius region at time peak flux. If another...
view Abstract Citations (406) References (41) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Neutron Star Accretion in a Supernova Chevalier, Roger A. An estimate can be made of the effect central mass on an explosion through study self-similar blast waves medium having inverse-square-of-r density profile, as is approximately case inner core progenitor SN 1987A; its parameters are such that nucleon substantially constant within shock front. In explosions...
We examine the case where a circumstellar medium around supernova is sufficiently opaque that radiation-dominated shock propagates in region. The initial propagation of front into region can be approximated by self-similar solution determines radiative energy shocked shell; eventual escape this gives maximum luminosity supernova. If density described ρ = Dr−2 out to radius Rw, D constant, properties breakout radiation depend on Rw and Rd ≡ κDvsh/c, κ opacity vsh velocity. Rw>Rd, rise light...
view Abstract Citations (647) References (43) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The Evolution of Supernova Remnants. Spherically Symmetric Models Chevalier, Roger A. evolution supernova remnants is studied using a spherically symmetric hydrodynamic code with magnetic field approximately included. Properties the emitted radiation are investigated. Particular attention paid to late phases when dense neutral shell forms which accretes matter from...
Type Ia supernovae are important cosmological distance indicators. Each of these bright supposedly results from the thermonuclear explosion a white dwarf star that, after accreting material companion star, exceeds some mass limit, but true nature progenitor system remains controversial. Here we report spectroscopic detection circumstellar in normal type supernova explosion. The expansion velocities, densities, and dimensions envelope indicate that this was ejected system. In particular,...
The double explosion of SN 2009ip in 2012 raises questions about our understanding the late stages massive star evolution. Here we present a comprehensive study during its remarkable rebrightenings. High-cadence photometric and spectroscopic observations from GeV to radio band obtained variety ground-based space facilities (including Very Large Array, Swift, Fermi, Hubble Space Telescope, XMM) constrain be low energy (E ∼ 1050 erg for an ejecta mass ∼0.5 M☉) asymmetric complex medium shaped...
HST and ground based observations of the Type IIn SN 2010jl are analyzed, including photometry, spectroscopy in ultraviolet, optical NIR bands, 26-1128 days after first detection. At maximum bolometric luminosity was $\sim 3\times10^{43}$ erg/s even at 850 exceeds $10^{42}$ erg/s. A excess, dominating 400 days, probably originates dust circumstellar medium (CSM). The total radiated energy is $> 6.5\times10^{50}$ ergs, excluding component. spectral lines can be separated into one broad...
Likely progenitors for gamma-ray bursts (GRBs) are the mergers of compact objects or explosions massive stars. These two cases have distinctive environments GRB afterglow: object occur in interstellar medium (ISM) and those stars preburst stellar wind. We calculate expected afterglow a burst Wolf-Rayet star wind compare results with constant, density. The optical case is generally to decline more steeply than constant density case, but this effect may be masked by variations electron...
The presumed Wolf-Rayet star progenitors of Type Ib/c supernovae have fast, low density winds and the shock waves generated by supernova interaction with wind are not expected to be radiative at typical times observation. injected energy spectrum radio emitting electrons typically has an observed index p=3, which is suggestive acceleration in cosmic ray dominated shocks. early, absorbed part light curves can attributed synchrotron self-absorption, leads constraints on magnetic field region...
HST images of the young supernova remnant Cas A are used to explore expansion and spatial distribution its highest velocity debris. ACS WFC taken in 2004 March December with Sloan F625W, F775W, F850LP filters were identify 1825 high-velocity, outlying ejecta knots through measured proper motions 035-090 yr-1, corresponding Vtrans = 5500-14,500 km s-1 assuming d 3.4 kpc. The derived transverse velocities for these shows a striking bipolar asymmetry (Vtrans ≥ 10,500 s-1) confined nearly...
view Abstract Citations (296) References (31) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Gravitational Collapse of an Isothermal Sphere Foster, Prudence N. ; Chevalier, Roger A. We investigate the spherical gravitational collapse isothermal spheres using numerical hydrodynamics. The initial configuration is close to hydrostatic equilibrium. If density profile has a finite core radius (i.e., it not singular), supersonic velocities develop during collapse....
Massive star supernovae can be divided into four categories depending on the amount of mass loss from progenitor and star's radius: red supergiant stars with most H envelope intact (SN IIP), some but lost (IIL, IIb), all (Ib, Ic), blue a massive 1987A-like). Various aspects immediate aftermath supernova are expected to develop in different ways category: mixing supernova, fallback central compact object, expansion any pulsar wind nebula, interaction circumstellar matter, photoionization by...
view Abstract Citations (230) References (70) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Circumstellar Interaction in SN 1993J Fransson, Claes ; Lundqvist, Peter Chevalier, Roger A. The radio and X-ray observations of during the first year can be consistently explained as a result interaction expanding ejecta with circumstellar medium. density gas deduced from free-free absorption emission luminosity. During 2 weeks, both sets indicate mass loss-rate ~4...
view Abstract Citations (300) References (39) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The optical emission from a fast shock wave with application to supernova remnants. Chevalier, R. A. ; Kirshner, P. Raymond, J. C. spectrum of Tycho's remnant was observed and only the H-alpha, H-beta, H-gamma lines were detected. H-alpha line profile can be divided into two components: one width consistent instrumental resolution full at half-maximum (FWHM) 1800...
Molecular clouds are known to be clumpy, with dense molecular clumps occupying only a few percent of the volume. A supernova remnant then evolves primarily in interclump medium, and becomes radiative at radius about 6 pc, forming shell that is magnetically supported. When this interacts clumps, shock fronts driven by considerable overpressure compared pressure rest remnant. Observations remnants W44 IC 443 can understood model. Both sources radio synchrotron emission, which attributed...