High energy neutrinos from pulsar-powered optical transients: LFBOTs as potential origin of the KM3NeT event KM3-230213A

TL;DR

The paper investigates whether a diffuse flux of high-energy neutrinos from pulsar-powered optical transients can account for the KM3NeT event KM3-230213A. By modeling magnetar-driven nebulae behind supernova ejecta and scanning the initial spin period $P_i$ and dipolar magnetic field $B_d$ across CCSNe, SLSNe, and LFBOTs, the authors compute both electromagnetic lightcurves and neutrino outputs, deriving a population-level diffuse flux. They find that LFBOTs, with $\varepsilon_ u^{\rm peak} \sim 10^{7}-10^{8}$ GeV and peak emission on multi-day timescales, can reproduce the joint flux while satisfying IceCube/Auger constraints; SLSNe and ordinary SNe can also contribute but require different parameter choices and rates. This work provides a testable, multi-messenger framework linking optical transients to UHE neutrino production and motivates stacking analyses with upcoming surveys and neutrino detectors to validate the proposed origin of KM3NeT events.

Abstract

Recently, the KM3NeT Collaboration reported the detection of an ultra-high energy ($\sim 220$ PeV) neutrino event, KM3-230213A. In this work, we perform a detailed investigation into whether this event could originate from the diffuse neutrino flux produced by a class of pulsar-powered optical transients. In particular, we consider populations of ordinary supernovae (SNe), super-luminous supernovae (SLSNe), and luminous fast blue optical transients (LFBOTs) with a newly formed magnetar as the central engine. We discuss both the thermal electromagnetic and non-thermal neutrino emission from such sources. We scan the parameter space of the dipolar magnetic field strength and the initial spin period to determine characteristic optical emission properties and lightcurve timescales of these transients. Additionally, our scan identifies which classes of these transients can reproduce the required diffuse flux level and neutrino energies. Combining our results, we conclude that a diffuse neutrino flux from a population of LFBOTs can explain the KM3NeT event. Therefore, pulsar-powered optical transients may serve as promising sources for the current and upcoming high-energy and ultra-high energy neutrino telescopes.

Figures (8)

• Figure 1: Time evolution of the bolometric luminosity ($L_{\rm bol}$) (top), thermal temperature ($T_{\rm th}$) (middle), and thermal (darker) and non-thermal (lighter) optical lightcurves in the $r$-band ($0.6\ \mu m$) (bottom) for three different parameter sets for LFBOTs. The time at which the bolometric luminosity peaks is defined as $t_{\rm pk}^{\rm therm}$ and is given by $t_{\rm pk}^{\rm therm} = 3.64, 3.9, 3.76$ days for $P_i = 1.6$ ms, $B_d = 6 \times 10^{13}$ G; $P_i = 3.2$ ms, $B_d = 8 \times 10^{13}$ G; and $P_i = 4.2$ ms, $B_d = 8 \times 10^{13}$ G respectively.
• Figure 2: Total energy fluence emitted in high energy neutrinos (all flavors) from a chosen parameter set for LFBOTs ($P_i = 1.6$ ms and $B_d = 6 \times 10^{13}$ G), plotted for various time intervals ranging from a few hours to few days post the collapse.
• Figure 3: Left: The absolute magnitude ($M_{\rm AB}$) of the optical thermal emission peak of r-band ($0.6\ \mu m$) for CCSNe (top) and LFBOTs (bottom) shown in the $B_d - P_i$ plane. For CCSNe two contours $M_{\rm AB} = -17$ (dashed light blue) and $M_{\rm AB} = -21$ (dotted maroon) denote the typical $M_{\rm AB}$ for ordinary SNe and SLSNe respectively, while for LFBOTs $M_{\rm AB} = -22$ (solid dark green) is also shown. Right: The fall time ($t_-$: the time interval in which the peak luminosity falls to half its value) for CCSNe (top) and LFBOTs (bottom) shown in the same $B_d - P_i$ plane. The typical fall-time values for ordinary SNe ($t_- \sim 25$ days) and SLSNe ($t_- \sim 40$ days) are shown in the same color scheme as before, while the same for LFBOTs ($t_- \sim 6$ days) is denoted by a solid dark green line. The LFBOT parameter set ($P_i = 1.6$ ms and $B_d = 6 \times 10^{13}$ G) (discussed in Section \ref{['sec:lfbot']}) which is the dominant contributor to the diffuse flux (see Section \ref{['sec:diffuse']}) is denoted using a star.
• Figure 4: The peak of total neutrino energy fluence ($E_{\nu,\rm tot}^{\rm peak}$) (left) and the peak energy in the neutrino spectrum ($\varepsilon_\nu^{\rm peak}$) (right) is shown in the $B_d - P_i$ plane for CCSNe (top) and LFBOTs (bottom). We also show the total energy budget in neutrinos needed to match the level of the joint flux's central value of $E_\nu^2 \phi_\nu \sim 7 \times 10^{-10}{\rm GeV}{\rm cm}^{-2}{\rm s}^{-1}{\rm sr}^{-1}$ as a dashed light blue contour for ordinary SNe, a dotted maroon contour for SLSNe, and a solid dark green contour for LFBOTs assuming $\dot{\rho}_0 = 10^{-5}\ {\rm Mpc}^{-3}\rm yr^{-1}$ for ordinary SNe and $\dot{\rho}_0 = 10^{-7}\ {\rm Mpc}^{-3}\rm yr^{-1}$ for SLSNe and LFBOTs. The LFBOT parameter set ($P_i = 1.6$ ms and $B_d = 6 \times 10^{13}$ G) (discussed in Section \ref{['sec:lfbot']}) which is the dominant contributor to the diffuse flux (see Section \ref{['sec:diffuse']}) is denoted using a star. Note that in the top right panel the white squares indicate $E_{\nu,\rm tot}^{\rm peak} < 10^{43}$ erg.
• Figure 5: The diffuse high energy neutrino spectrum from a population of LFBOTs (see Equation \ref{['eq:diffuse']} and Section \ref{['appsec:diffuse_comp']}). The shaded purple band shows the 40% uncertainty in the diffuse flux. The light blue cross denotes the joint flux obtained from KM3NeT:2025ccp by including IceCube Extreme High-energy (IC-EHE) IceCube:2018fhm and Auger non-observations along with the updated IceCube IceCubeCollaborationSS:2025jbi and differential upper limits from Auger PierreAuger:2023pjg. The diffuse upper limits from ANTARES at 95% C.L. ANTARES:2024ihw, Auger at 90% C.L. PierreAuger:2023pjg, and IC-EHE at 90% C.L. IceCube:2018fhm are shown as dashed gray lines. The light orange and light green shaded regions represent the 68% C.L. contours of the IceCube single power-law (SPL) fits to the Northern Sky Tracks (NST) Abbasi:2021qfz and High Energy Starting Events (HESE) IceCube:2020wum datasets. The segmented fits from the same datasets are shown with light orange and light green crosses respectively. Additionally, the Glashow resonance event at IceCube IceCube:2021rpz is shown in yellow. The equivalent flux for KM3-230213A KM3NeT:2025npi is shown using gray lines along with the $1 \sigma$, $2 \sigma$, and $3 \sigma$ uncertainty bands in darker shades of gray.