923 research outputs found
Self-induced tunable transparency in layered superconductors
We predict a novel nonlinear electromagnetic phenomenon in layered
superconducting slabs irradiated from one side by an electromagnetic plane
wave. We show that the reflectance and transmittance of the slab can vary over
a wide range, from nearly zero to one, when changing the incident wave
amplitude. Thus changing the amplitude of the incident wave can induce either
the total transmission or reflection of the incident wave. In addition, the
dependence of the superconductor transmittance on the incident wave amplitude
has an unusual hysteretic behavior with jumps. This remarkable nonlinear effect
(self-induced transparency) can be observed even at small amplitudes, when the
wave frequency is close to the Josephson plasma frequency .Comment: 9 pages, 7 figure
Light Curve Models of Supernovae and X-ray spectra of Supernova Remnants
We compare parameters of well-observed type II SN1999em derived by M.Hamuy
and D.Nadyozhin based on Litvinova-Nadyozhin (1985) analytic fits with those
found from the simulations with our radiative hydro code Stella. The difference
of SN parameters is quite large for the long distance scale. The same code
applied to models of SN1993J allows us to estimate systematic errors of
extracting foreground extinction toward SN1993J suggested by Clocchiatti et al.
(1995). A new implicit two-temperature hydro code code Supremna is introduced
which self-consistently takes into account the kinetics of ionization, electron
thermal conduction, and radiative losses for predicting X-ray spectra of young
supernova remnants such as Tycho and Kepler.Comment: 7 pages, 10 figures, Supernovae as Cosmological Lighthouses, Padua,
June 16- 19, 2004, eds. M.Turatto et al., ASP Conference Serie
Early light curves for Type Ia supernova explosion models
Upcoming high-cadence transient survey programmes will produce a wealth of
observational data for Type Ia supernovae. These data sets will contain
numerous events detected very early in their evolution, shortly after
explosion. Here, we present synthetic light curves, calculated with the
radiation hydrodynamical approach Stella for a number of different explosion
models, specifically focusing on these first few days after explosion. We show
that overall the early light curve evolution is similar for most of the
investigated models. Characteristic imprints are induced by radioactive
material located close to the surface. However, these are very similar to the
signatures expected from ejecta-CSM or ejecta-companion interaction. Apart from
the pure deflagration explosion models, none of our synthetic light curves
exhibit the commonly assumed power-law rise. We demonstrate that this can lead
to substantial errors in the determination of the time of explosion. In
summary, we illustrate with our calculations that even with very early data an
identification of specific explosion scenarios is challenging, if only
photometric observations are available.Comment: 15 pages, 14 figures, 3 tables, accepted for publication in MNRA
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