First Associated Neutrino Search for a Failed Supernova Candidate with Super-Kamiokande

TL;DR

This study tests whether a recently reported extragalactic failed supernova candidate, M31-2014-DS1, emitted detectable electron antineutrinos at Earth by performing a targeted time-cluster search with Super-Kamiokande. A dedicated analysis defines a 10-second signal window and an $18~\mathrm{MeV}$ energy threshold, with signal and background time ranges informed by optical constraints on black hole formation. No statistically significant neutrino cluster is found, and the authors derive 90% C.L. upper limits on the electron antineutrino luminosity, notably constraining the Shen-TM1 EOS with $L_{\bar{\nu}_e}^{90\%} = 1.76\times 10^{53}$ erg, near the model prediction. The work demonstrates the feasibility of extragalactic failed SN neutrino searches and outlines future improvements with larger detectors (HK, JUNO, DUNE) and enhanced optical surveys (LSST, LBT, Subaru/HSC).

Abstract

In 2024, a failed supernova candidate, M31-2014-DS1, was reported in the Andromeda galaxy (M31), located at a distance of approximately 770 kpc. In this paper, we search for neutrinos from this failed supernova using data from Super-Kamiokande (SK). Based on the estimated time of black hole formation inferred from optical and infrared observations, we define a search window for neutrino events in the SK data. Using this window, we develop a dedicated analysis method for failed supernovae and apply it to M31-2014-DS1, by conducting a cluster search using the timing and energy information of candidate events. No significant neutrino excess is observed within the search region. Consequently, we place an upper limit on the electron antineutrino luminosity from M31-2014-DS1 and discuss its implications for various failed SN models and their neutrino emission characteristics. Despite the 18 MeV threshold adopted to suppress backgrounds, the search remains sufficiently sensitive to constrain the Shen-TM1 EOS, yielding a 90% confidence level upper limit of 1.76 \times 10^{53} erg on the electron antineutrino luminosity, slightly above the expected value of 1.35 \times 10^{53} erg.

Figures (4)

• Figure 1: Livetime fraction of SK used in this analysis. The blue line indicate the effective livetime fraction for each month, while the red solid lines show the yearly averaged effective livetime fraction. The red dashed lines represent the standard deviation of the yearly mean. The loss of livetime is mainly attributed to detector calibrations and maintenance periods.
• Figure 2: The expected probability of observing clusters due to background events at each energy threshold. The red points indicate the probability of observing one or more clusters within the signal time range. The black and green lines represent the fractions of trials without any clusters at the $2\sigma$ and $3\sigma$ levels, respectively.
• Figure 3: Upper limits on the neutrino luminosity for each failed SN model. The models are arranged from left to right in order of decreasing predicted luminosity. The star marks the predicted luminosity of the model, while the black downward arrow indicates the $90\%$ C.L. upper limit obtained in the present work. The circle points show the average energy for each model, plotted with the right vertical axis, while the luminosity is shown with the left axis. From left to right, the models correspond to 2021Nakazato2007Sumiyoshi2008Sumiyoshi2025Choi.
• Figure 4: Electron antineutrino luminosity $L_{\nu}$ versus mean energy $\langle E_{\bar{\nu}_e} \rangle$. Shaded regions (light to dark cyan) represent the probability contours (50%, 68%, 90%, 95%, and 99%) for detecting at least two correlated events in SK, based on Poisson statistics for a source located at 770 kpc. The regions above these bands are excluded based on the nondetection of time-clustered events in SK. Filled markers show individual simulation results for six nuclear equations of state (EOS): LS180, LS220, SFHo, Togashi, Shen-TM1e, and Shen-TM1. Each model corresponds to Figure 1 and Table 1 in 2025Suwa. The blue dashed line indicates the 90% probability contour for a detector with ten times the fiducial mass of SK, assuming Poisson statistics for a source at the distance of $770~\rm{kpc}$.