Improved analysis of SN1987A antineutrino events
arXiv:0810.0466 · doi:10.1016/j.astropartphys.2008.12.010
Abstract
We propose a new parameterization of the antineutrino flux from core collapse supernovae, that allows an interpretation of its astrophysical parameters within the Bethe and Wilson scenario for the explosion, and that leads to a reasonable (smooth) behavior of the average energy and of the luminosity curve. We apply it to analyze the events observed by Kamiokande-II, IMB and Baksan detectors in correlation with SN1987A. For the first time, we consider in the same analysis all data characteristics: times, energies and angles of the observed events. We account for the presence of background and evaluate the impact of neutrino oscillations. The hypothesis that the initial luminous phase of emission (accretion) is absent can be rejected at the 2 % significance level. Without the need to impose external priors in the likelihood analysis, the best-fit values of the astrophysical parameters are found to be in remarkable agreement with the expectations of the standard core-collapse scenario; in particular, the electron antineutrino-sphere radius is 16 km, the duration of the accretion phase is found to be 0.55 s, and the initial accreting mass is 0.22 M(sun). Similarly the total energy emitted in neutrinos is 2.2*10^{53} erg, again close to the expectations. The errors on the parameters are evaluated and found to be relatively large, consistently with the limited number of detected events; the two dimensional confidence regions, that demonstrate the main correlations between the parameters, are also given.
15 pages, 5 figures
References in corpus (12)
- Collective neutrino flavor transitions in supernovae and the role of trajectory averaging
- Role of dense matter in collective supernova neutrino transformations
- Analysis of Collective Neutrino Flavor Transformation in Supernovae
- Neutrino Mass Hierarchy and Stepwise Spectral Swapping of Supernova Neutrino Flavors
- Identifying neutrino mass hierarchy at extremely small theta(13) through Earth matter effects in a supernova signal
- Mu-tau neutrino refraction and collective three-flavor transformations in supernovae
- Study of the effect of neutrino oscillations on the supernova neutrino signal in the LVD detector
- Formation of quark phases in compact stars and SN explosion
- Supernova explosions and the birth of neutron stars
- Neutrino-driven explosions twenty years after SN1987A
- The first second of SN1987A neutrino emission
- How much can we learn from SN1987A events? Or: An analysis with a two-Component model for the antineutrino signal