Speaker
Description
The Large High Altitude Air Shower Observatory (LHAASO) observed a giant $\gamma$-ray bubble from the direction of the Galactic star-forming region Cygnus-X. The morphology and the energy spectrum of the bubble suggest that these $\gamma$-rays are correlated to the interactions between cosmic rays and gas clumps, indicating the expectation of an extended neutrino counterpart. Using public IceCube muon-track data, we found hints of neutrino signals exceeding both the atmospheric background and isotropic astrophysical neutrinos within the bubble, with a post-trial significance of $1.7\sigma$. Interestingly, within $0.7^{\circ}$ of the bubble center, the neutrino signals show a notable excess over expectations, even if all $\gamma$-rays of Cygnus bubble are of hadronic origin. To explain observations, we proposed that neutrinos primarily originate from a central $\gamma$-ray hidden source, with the microquasar Cygnus X-3 dominating the excess. This finding hints at microquasars as potential sources of high-energy neutrinos. Next-generation neutrino telescopes at the $10\,{\rm km^3}$ scale could have the capability to identify these sources.
