Possible Neutrino Emission from the Pulsar Wind Nebula G63.7+1.1

TL;DR

This paper reports the potential detection of high-energy neutrinos from the pulsar wind nebula G63.7+1.1, suggesting PWNe could be significant sources of Galactic neutrinos based on IceCube data analysis.

Contribution

It presents the first possible neutrino emission detection from a PWN, highlighting the role of proton-proton interactions in neutrino production within PWNe.

Findings

Detected an excess of neutrinos at G63.7+1.1 with 3.2σ significance.

G63.7+1.1 is the only PWN among 14 analyzed with neutrino emission.

Surrounding molecular clouds may facilitate proton interactions leading to neutrino production.

Abstract

We report on our finding of an excess of $54^{+16}_{-15}$ neutrinos at the location of the pulsar wind nebula (PWN) G63.7+1.1. By analyzing the IceCube track-like neutrino data for a group of 14 PWNe, which are selected as the targets because of their reportedly association with molecular clouds, G63.7+1.1 is found to be the only one detected with neutrino emission and the post-trail significance for the detection is 3.2$\sigma$. Previously, this PWN was estimated to have an age of $\gtrsim$8\,kyr, contain a candidate pulsar detected in X-rays, and have a distance of $\sim$6\,kpc. More importantly and related to the PWN's possible neutrino emission, surrounding molecular materials are seen to interact with the PWN. On the basis of these properties, we examine the proton-proton interactions as the process for the neutrino production. The PWN (or the pulsar) can collectively provide sufficient energy to power the required high-energy (HE) protons. This possibly first neutrino-emitting case in our Galaxy, with problems or other possibilities to be solved or examined, may reveal to us that PWNe are the significant Galactic HE neutrino sources.