Searches for Neutrinos from LHAASO ultra-high-energy {\gamma}-ray sources using the IceCube Neutrino Observatory

TL;DR

This study searches for neutrino emissions from 12 ultra-high-energy gamma-ray sources identified by LHAASO, using 11 years of IceCube data, to test the hadronic origin of their gamma-ray emissions, but finds no significant neutrino signals.

Contribution

First comprehensive search for neutrinos from LHAASO gamma-ray sources using IceCube data, constraining hadronic contributions in these PeVatrons.

Findings

No significant neutrino emission detected from the sources.

Constraints placed on the hadronic contribution to gamma-ray flux.

Limits inform models of cosmic-ray acceleration in Galactic sources.

Abstract

Galactic PeVatrons are Galactic sources theorized to accelerate cosmic rays up to PeV in energy. The accelerated cosmic rays are expected to interact hadronically with nearby ambient gas or the interstellar medium, resulting in {\gamma}-rays and neutrinos. Recently, the Large High Altitude Air Shower Observatory (LHAASO) identified 12 {\gamma}-ray sources with emissions above 100 TeV, making them candidates for PeV cosmic-ray accelerators (PeVatrons). While at these high energies the Klein-Nishina effect suppresses exponentially leptonic emission from Galactic sources, evidence for neutrino emission would unequivocally confirm hadronic acceleration. Here, we present the results of a search for neutrinos from these {\gamma}-ray sources and stacking searches testing for excess neutrino emission from all 12 sources as well as their subcatalogs of supernova remnants and pulsar wind nebulae with 11 years of track events from the IceCube Neutrino Observatory. No significant emissions were found. Based on the resulting limits, we place constraints on the fraction of {\gamma}-ray flux originating from the hadronic processes in the Crab Nebula and LHAASOJ2226+6057.