Neutrino Lighthouse at Sagittarius A*

TL;DR

This paper explores the potential link between high-energy neutrino events detected by IceCube and X-ray flares from Sagittarius A*, suggesting it could be a point source of such neutrinos and proposing observational tests.

Contribution

It presents evidence of temporal coincidence between IceCube neutrino events and Sagittarius A* flares, proposing Sagittarius A* as a neutrino source and outlining observational strategies for confirmation.

Findings

Event 25 occurred shortly after a Sagittarius A* X-ray flare with high significance.

Two neutrino events occurred within one day, indicating possible burst activity.

Gamma-ray observations could confirm the neutrino source through pion decay signatures.

Abstract

We investigate whether a subset of high-energy events observed by IceCube may be due to neutrinos from Sagittarius A*. We check both spatial and temporal coincidences of IceCube events with other transient activities of Sagittarius A*. Among the seven IceCube shower events nearest to the galactic center, we have found that event 25 has a time very close to (around three hours after) the brightest X-ray flare of Sagittarius A* observed by the Chandra X-ray Observatory with a p-value of 0.9%. Furthermore, two of the seven events occurred within one day of each other (there is a 1.6% probability that this would occur for a random distribution in time). Thus, the determination that some IceCube events occur at similar times as X-ray flares and others occur in a burst could be the smoking gun that Sagittarius A* is a point source of very high energy neutrinos. We point out that if IceCube galactic center neutrino events originate from charged pion decays, then TeV gamma rays should come from neutral pion decays at a similar rate. We show that the CTA, HAWC, H.E.S.S. and VERITAS experiments should be sensitive enough to test this.