Almost 30 years have passed since the successful detection of supernova neutrinos from SN 1987A. In the last decades, remarkable progress has been made in neutrino detection technique, through which it may be possible to detect neutrinos from a new source, pre-supernova (pre-SN) neutrinos. They are emitted from a massive star prior to core bounce. Because neutrinos escape from the core freely, they carry information about the stellar physics directly. Pre-SN neutrinos may play an important role in verifying our understanding of stellar evolution for massive stars. Observations of pre-SN neutrinos, moreover, may serve as an alarm regarding a supernova explosion a few days in advance if the progenitor is located in our vicinity, enabling us to observe the next galactic supernova. In this review, we summarize the current status of pre-SN neutrino studies from both of the theoretical and observational points of view.
We explore the potential of current and future liquid scintillator neutrino detectors of O (10) kt mass to localize a pre-supernova neutrino signal in the sky. In the hours preceding the core collapse of a nearby star (at distance D < 1 kpc), tens to hundreds of inverse beta decay events will be recorded, and their reconstructed topology in the detector can be used to estimate the direction to the star. Although the directionality of inverse beta decay is weak (~8% forward-backward asymmetry for currently available liquid scintillators), we find that for a fiducial signal of 200 events (which …
Binary population synthesis (BPS) employs prescriptions to predict final fates, explosion or implosion, and remnant masses based on one or two stellar parameters at the evolutionary cutoff imposed by the code, usually at or near central carbon ignition. In doing this, BPS disregards the integral role late-stage evolution plays in determining the final fate, remnant type, and remnant mass within the neutrino-driven explosion paradigm. To highlight differences between a popular prescription which relies only on the core and final stellar mass and emerging methods which rely on a star's presupern…
Supernova neutrino detection in neutrino and dark matter experiments is usually implemented as a real-time trigger system based on counting neutrino interactions within a moving time window. The sensitivity reach of such experiments can be improved by taking into account the time profile of the expected signal. We propose a shape analysis of the incoming experimental data based on a log likelihood ratio variable containing the assumed signal shape. This approach also allows a combination of potential supernova signals in different detectors for a further sensitivity boost. The method is tested…
We study the effects of the magnetic field on the dynamics of non-rotating stellar cores by performing two-dimensional (2D), magnetohydrodynamics (MHD) simulations. To this end, we have updated our neutrino-radiation-hydrodynamics supernova code to include MHD employing a divergence cleaning method with both careful treatments of finite volume and area reconstructions. By changing the initial strength of the magnetic field, the evolution of $15.0$, $18.4$ and $27.0$ $M_\odot$ presupernova progenitors is investigated. An intriguing finding in our study is that the neutrino-driven explosion occu…
This contribution reviews recent advances in the possible identification of blazars as potential sources of at least some of the very-high-energy neutrinos detected by the IceCube neutrino detector at the South Pole. The basic physical requirements for neutrino production and physics constraints that may be drawn from neutrino - blazar associations are reviewed. Several individual cases of possible associations will be discussed in more detail. It is emphasized that due to $γγ$ opacity constraints in efficiently neutrino-producing blazars, an association between X-ray -- soft $γ$-ray activity …
Six binary-merger progenitors of Supernova 1987A (SN 1987A) with properties close to those of the blue supergiant Sanduleak -69 202 are exploded by neutrino heating and evolved until long after shock breakout in three dimensions (3D), and continued for light-curve calculations in spherical symmetry. Our results confirm previous findings for single-star progenitors: (1) 3D neutrino-driven explosions with SN 1987A-like energies synthesize Ni-56 masses consistent with the radioactive light-curve tail; (2) hydrodynamic models mix hydrogen inward to minimum velocities below 40 km/s compatible with …
The observation of a neutrino at IceCube in association with the Tidal Disruption Event (TDE) AT2019dsg has suggested TDEs as a new class of sources of astrophysical neutrinos. We present a model of this multi-messenger observation in a jetted concordance scenario, where the neutrino production is directly linked to the observed X-rays, and the timing of the neutrino observation (about 150 days post peak) can be naturally described. We briefly discuss the implications of our model for future neutrino-TDE associations.
Theoretical predictions of the prompt atmospheric neutrino flux have large uncertainties associated with charm hadron production, by far the dominant source of prompt neutrinos in the atmosphere. The flux of cosmic rays, with its steeply falling energy spectrum, weights the forward production of charm in the evaluation of the atmospheric neutrino flux at high energies. The current LHCb experiment at CERN constrains charm production in kinematic regions relevant to the prompt atmospheric neutrino flux. The proposed Forward Physics Facility has additional capabilities to detect neutrino fluxes f…
