A New Multi-Dimensional General Relativistic Neutrino Hydrodynamics Code for Core-Collapse Supernovae. Iv. The Neutrino Signal

Abstract

Considering six general relativistic, two-dimensional (2D) supernova (SN) explosion models of progenitor stars between 8.1 and 27 M ⊙ , we systematically analyze the properties of the neutrino emission from core collapse and bounce to the post-explosion phase. The models were computed with the Vertex-CoCoNuT code, using three-flavor, energy-dependent neutrino transport in the ray-by-ray-plus approximation. Our results confirm the close similarity of the mean energies, E , ofν e and heavy-lepton neutrinos and even their crossing during the accretion phase for stars with M 10 M ⊙ as observed in previous 1D and 2D simulations with stateof-the-art neutrino transport. We establish a roughly linear scaling of Eν e with the proto-neutron star (PNS) mass, which holds in time as well as for different progenitors. Convection inside the PNS affects the neutrino emission on the 10-20% level, and accretion continuing beyond the onset of the explosion prevents the abrupt drop of the neutrino luminosities seen in artificially exploded 1D models. We demonstrate that a waveletbased time-frequency analysis of SN neutrino signals in IceCube will offer sensitive diagnostics for the SN core dynamics up to at least ∼10 kpc distance. Strong, narrow-band signal modulations indicate quasi-periodic shock sloshing motions due to the standing accretion shock instability (SASI), and the frequency evolution of such "SASI neutrino chirps" reveals shock expansion or contraction. The onset of the explosion is accompanied by a shift of the modulation frequency below 40-50 Hz, and post-explosion, episodic accretion downflows will be signaled by activity intervals stretching over an extended frequency range in the wavelet spectrogram.

The Criterion of Supernova Explosion Revisited: The Mass Accretion History

“…We can then evaluate the neutrino luminosity as Equation (6). This phenomenological model is consistent with the finding by Fischer et al (2009) and Müller & Janka (2014) that the neutrino luminosity seems to be regulated by the smaller of the accretion and diffusion luminosities. Indeed, sincẽ , and R ν =50 km in Equations (4) and (7).…”

Should One Use the Ray-by-Ray Approximation in Core-Collapse Supernova Simulations?

“…The Garching group, using the CoCoNuT hydrodynamics code (Müller et al 2012ab;Müller & Janka 2014) in combination with the VERTEX transport solver, or their earlier VERTEX-PROMETHEUS code , has also obtained tepid explosions in 2D, and in 3D only when altering the physics (Melson et al 2015). Suwa et al (2014), Takiwaki et al (2012), and Iwakami, Nagakura, & Yamada (2014) neglect ν µ and ν τ neutrinos and use the simplifying IDSA technique (Liebendörfer et al 2009); they also obtain explosions in 2D and have explored 3D simulations at low resolution.…”

Supernovae and Weinberg’s Higgs portal dark radiation and dark matter

“…Thanks to its proximity of about 51 kpc to the Earth, neutrino burst events from the core collapse of the progenitor star could be recorded at the underground laboratories Irvine-Michigan-Brookhaven (IMB), Kamiokande II, and Baksan separately [1]. The observed burst duration of about 12 seconds, individual energies up to 40 MeV, as well as the integrated total energy of O(10 53 erg), confirmed the standard picture of neutrino cooling of the proto-neutron star (PNS) [2][3][4]. A proto-neutron star is formed when the collapsing stellar core of the progenitor star reaches nuclear saturation density.…”

“…Here we also checked that Goldstone boson production can be well described by the production of a real light Higgs boson and its subsequent decay. We compare the results in these two limits at the nuclear saturation density ρ = 3 · 10 14 g/cm 3 . In figure 1 the comparison is made at the PNS core temperature T = 30 MeV and neutron fraction X n = 1 and 0.7.…”