  Astrophysical sources of neutrinos detected by large-scale neutrino
telescopes remain uncertain. While there exist statistically significant
observational indications that a part of the neutrino flux is produced by
blazars, numerous theoretical studies suggest also the presence of potential
Galactic point sources. Some of them have been observed in gamma rays above 100
TeV. Moreover, cosmic-ray interactions in the Galactic disk guarantee a diffuse
neutrino flux. However, these Galactic neutrinos have not been unambiguously
detected so far. Here we examine whether such a Galactic component is present
among the observed neutrinos of the highest energies. We analyze public
track-like IceCube events with estimated neutrino energies above 200 TeV. We
examine the distribution of arrival directions of these neutrinos in the
Galactic latitude b with the help of a simple unbinned, non-parametric test
statistics, the median |b| over the sample. This distribution deviates from
that implied by the null hypothesis of the neutrino flux isotropy, and is
shifted towards lower b with the p-value of 4*10^{-5}, corresponding to the
statistical significance of 4.1 sigma. There exists a significant component of
the high-energy neutrino flux of Galactic origin, matching well the
multi-messenger expectations from Tibet-ASgamma observations of diffuse
Galactic gamma rays at hundreds of TeV. Together with the previously
established extragalactic associations, the Galactic component we report here
implies that the neutrino sky is rich and is composed of contributions from
various classes of sources.
