Searching for a Galactic component in the IceCube track-like neutrino events

Abstract

Searches for spatial associations between high-energy neutrinos observed at the IceCube Neutrino Observatory and known astronomical objects may hold the key to establishing the neutrinos' origins and the origins of hadronic cosmic rays. While extragalactic sources like the blazar TXS 0506+056 merit significant attention, Galactic sources may also represent part of the puzzle. Here, we explore whether open clusters and supernova remnants in the Milky Way contribute measurably to the IceCube track-like neutrino events above 200 TeV. By searching for positional coincidences with catalogs of known astronomical objects, we can identify and investigate neutrino events whose origins are potentially Galactic. We use Monte Carlo randomization together with models of the Galactic plane in order to determine whether these coincidences are more likely to be causal associations or random chance. In all analyses presented, the number of coincidences detected was found to be consistent with the null hypothesis of chance coincidence. Our results imply that the combined contribution of Galactic open clusters and supernova remnants to the track-like neutrino events detected at IceCube is well under 30%. This upper limit is compatible with the results presented in other Galactic neutrino studies.

A stacked search for spatial coincidences between IceCube neutrinos and radio pulsars

“…In a similar vein, a galactic contribution to the all-sky IceCube diffuse neutrino flux cannot be excluded and has been estimated to be about 10-20% [19]. Therefore, searches for coincidences with multiple galactic sources have also been carried out [20]. One such source includes pulsars, which are rapidly rotating neutron stars which emit pulsed radio emission [21].…”

Search for spatial coincidence between IceCube neutrinos and radio pulsars

“…Therefore, for the above reasons, a large number of works have explored possible contributions from galactic sources to the IceCube diffuse neutrino flux. This includes individual sources such as supernova remnants, X-ray binaries, pulsar wind nebulae, open clusters, LHAASO sources, as well as a diffuse galactic component due to cosmic ray interactions with the interstellar medium [10][11][12][13][14][15][16][17]. It is also important to look for coincidences sources which have hitherto not been considered.…”