Search results for "Supernova"
showing 10 items of 330 documents
Parameter Degeneracy in Flavor-Dependent Reconstruction of Supernova Neutrino Fluxes
2008
We reexamine the possibility of reconstructing the initial fluxes of supernova neutrinos emitted in a future core-collapse galactic supernova explosion and detected in a Megaton-sized water Cherenkov detector. A novel key element in our method is the inclusion, in addition to the total and the average energies of each neutrino species, of a "pinching" parameter characterizing the width of the distribution as a fit parameter. We uncover in this case a continuous degeneracy in the reconstructed parameters of supernova neutrino fluxes at the neutrinosphere. We analyze in detail the features of this degeneracy and show how it occurs irrespective of the parametrization used for the distribution …
New Supernova Constraints on active-sterile neutrino conversions
1994
We consider active-sterile neutrino conversions in a supernova in the presence of random magnetic field domains. For large enough fields the magnetization of the medium may enhance the active to sterile neutrino conversion rates. Neglecting neutrino transition magnetic moments we show that for KeV neutrino mass squared differences these limits may overcome those that would apply in the isotropic case.
Evolution of Proto-Neutron stars with kaon condensates
2000
We present simulations of the evolution of a proto-neutron star in which kaon-condensed matter might exist, including the effects of finite temperature and trapped neutrinos. The phase transition from pure nucleonic matter to the kaon condensate phase is described using Gibbs' rules for phase equilibrium, which permit the existence of a mixed phase. A general property of neutron stars containing kaon condensates, as well as other forms of strangeness, is that the maximum mass for cold, neutrino-free matter can be less than the maximum mass for matter containing trapped neutrinos or which has a finite entropy. A proto-neutron star formed with a baryon mass exceeding that of the maximum mass …
Detecting the Diffuse Supernova Neutrino Background in the future Water-based Liquid Scintillator Detector Theia
2021
A large-scale neutrino observatory based on water-based liquid scintillator (WbLS) will be excellently suited for a measurement of the diffuse supernova neutrino background (DSNB). The WbLS technique offers high signal efficiency and effective suppression of the otherwise overwhelming background from neutral-current interactions of atmospheric neutrinos. To illustrate this, we investigate the DSNB sensitivity for two configurations of the future Theia detector by developing the expected signal and background rejection efficiencies along a full analysis chain. Based on a statistical analysis of the remaining signal and background rates, we find that a rather moderate exposure of $190\text{ }…
Search for Supernova Neutrino-Bursts with the AMANDA Detector
2001
The core collapse of a massive star in the Milky Way will produce a neutrino burst, intense enough to be detected by existing underground detectors. The AMANDA neutrino telescope located deep in the South Pole ice can detect MeV neutrinos by a collective rate increase in all photo-multipliers on top of dark noise. The main source of light comes from positrons produced in the CC-reaction of anti-electron neutrinos on free protons $\antinue + p \to e^+ + n$. This paper describes the first supernova search performed on the full sets of data taken during 1997 and 1998 (215 days of live time) with 302 of the detector's optical modules. No candidate events resulted from this search. The performan…
Physics potential of the Jiangmen underground neutrino observatory
2019
JUNO (Jiangmen Underground Neutrino Observatory) is a 20 kton multipurpose neutrinodetector under construction in China and it will be completed in 2021. The detector will belocated near the the city of Jiangmen, 53 km away from two nuclear power plants that willprovide the neutrino flux for the main sear of the observatory. The main physics goal is the determination of the neutrino Mass Hierarchy, even if will play animportant also in other topics, such as: neutrino oscillation, solar neutrino, SuperNova neutrinos,geoneutrinos and atmosperic neutrinos among others
The importance of magnetic-field-oriented thermal conduction in the interaction of SNR shocks with interstellar clouds
2008
We explore the importance of magnetic-field-oriented thermal conduction in the interaction of supernova remnant (SNR) shocks with radiative gas clouds and in determining the mass and energy exchange between the clouds and the hot surrounding medium. We perform 2.5D MHD simulations of a shock impacting on an isolated gas cloud, including anisotropic thermal conduction and radiative cooling; we consider the representative case of a Mach 50 shock impacting on a cloud ten-fold denser than the ambient medium. We consider different configurations of the ambient magnetic field and compare MHD models with or without the thermal conduction. The efficiency of the thermal conduction in the presence of…
Semi-global simulations of the magneto-rotational instability in core collapse supernovae
2009
Possible effects of magnetic fields in core collapse supernovae rely on an efficient amplification of the weak pre-collapse fields. It has been suggested that the magneto-rotational instability (MRI) leads to rapid field growth. Although MRI studies exist for accretion discs, the application of their results to core collapse supernovae is inhibited as the physics of supernova cores is substantially different from that of accretion discs. We address the problem of growth and saturation of the MRI by means of semi-global simulations, which combine elements of global and local simulations by taking the presence of global background gradients into account and using a local computational grid. W…
Hydrodynamic simulations of the interaction of supernova shock waves with a clumpy environment: the case of the RX J0852.0-4622 (Vela Jr.) supernova …
2013
Observations in all electromagnetic bands show that many supernova remnants (SNRs) have a very aspherical shape. This can be the result of asymmetries in the supernova explosion or a clumpy circumstellar medium. We study the generation of inhomogeneities and the mixing of elements arising from these two sources in multidimensional hydrodynamic simulations of the propagation of a supernova blast wave into a cloudy environment. We model a specific SNR, Vela Jr (RX J0852.0-4622). By comparing our results with recent observations, we can constrain the properties of the explosion. We find that a very energetic explosion of several 10^{51} erg occurring roughly about 800 years ago is consistent w…
Hydrodynamic modelling of ejecta shrapnel in the Vela supernova remnant
2013
Many supernova remnants (SNRs) are characterized by a knotty ejecta structure. The Vela SNR is an excellent example of remnant in which detached clumps of ejecta are visible as X-ray emitting bullets that have been observed and studied in great detail. We aim at modelling the evolution of ejecta shrapnel in the Vela SNR, investigating the role of their initial parameters (position and density) and addressing the effects of thermal conduction and radiative losses. We performed a set of 2-D hydrodynamic simulations describing the evolution of a density inhomogeneity in the ejecta profile. We explored different initial setups. We found that the final position of the shrapnel is very sensitive …