Rotational Effects on Neutrino Emission in Core-collapse Supernovae

Abstract

All stars rotate. While magnetic braking slows massive stars, the effect a stellar companion has on stellar rotation is still being explored. To prepare for future observations from rotating core-collapse supernovae (CCSNe), we analyze a set of 30 2D neutrino radiation-hydrodynamic CCSN simulations for a variety of compactness values, rotation rates, and equations of state. We systematically explore how rotation lowers expected neutrino counts and energies for a realistic detector, while accounting for adiabatic Mikheyev-Smirnov-Wolfenstein matter effects. We quantify the effect of viewing angle for neutrino emission for multiple rotation rates. Using 'multimessenger synthesis', we develop a technique that correlates multimessengers to constrain the neutrino mass ordering for a future supernova event. Likewise, we develop a method to constrain the distance to a rotating or nonrotating CCSN, regardless of explosion outcome.

Figures (14)

• Figure 1: Shock radius evolution for all 30 $M_\odot$ models at different rotation rates, in units of rad s$^{-1}$. The $\Omega_0 = 0,0.5,3$ rad s$^{-1}$ cases show advancing shock radii after 300 ms.
• Figure 2: Angle-averaged antineutrino luminosity ($L_{\bar{\nu}_e}$) time evolution for nonrotating simulations. The neutrino light curves show expected higher peak $L_{\bar{\nu}_e}$ with increasing compactness, sourced from higher mass accretion rates.
• Figure 3: Angle averaged electron-type antineutrino luminosity ($L_{\bar{\nu}_e}$) time evolution. We observe the expected decrease in luminosity as the central rotation rate $\Omega_0$ [rad s$^{-1}$] is increased, corresponding to centrifugal support.
• Figure 4: Accretion phase neutrino counts seen by a 32 kton SuperKamiokande-like detector. Simulations are ordered first by ZAMS mass and then by central rotation rate $\Omega_0$. The counts depend on progenitor compactness and rotation rate. The influence of the EOS on accretion phase counts can be seen by comparing the s20o* models. When incorporating the adiabatic MSW effect, assuming the normal mass ordering (NMO) and inverted mass ordering (IMO), the observed counts drop for this kind of detector. The assumed CCSN distance is 10 kpc.
• Figure 5: Neutrino counts during the accretion phase ($N_{\rm accretion}$) versus $\xi_{1.75}$ for all nonrotating models. The difference between the red square and two blue triangles displays the EOS dependence of observed neutrino emission for the $20 M_\odot$ models. The functional form of these relations is preserved, though shifted, for different mixing schemes. Note the different axis limits in the right panel.