We present the results of a search for point sources of high-energy neutrinos in the northern hemisphere using AMANDA-II data collected in the year 2000. Included are flux limits on several active-galactic-nuclei blazars, microquasars, magnetars, and other candidate neutrino sources. A search for excesses above a random background of cosmic-ray-induced atmospheric neutrinos and misreconstructed downgoing cosmic-ray muons reveals no statistically significant neutrino point sources. We show that AMANDA-II has achieved the sensitivity required to probe known TeV $\gamma$-ray sources such as the blazar Markarian 501 in its 1997 flaring state at a level where neutrino and $\gamma$-ray fluxes are equal.

• Received 19 September 2003

DOI:https://doi.org/10.1103/PhysRevLett.92.071102