Very High-Energy Gamma-Ray Follow-Up Program Using Neutrino Triggers   from IceCube
  We describe and report the status of a neutrino-triggered program in IceCube that generates real-time alerts for gamma-ray follow-up observations by atmospheric-Cherenkov telescopes (MAGIC and VERITAS). While IceCube is capable of monitoring the whole sky continuously, high-energy gamma-ray telescopes have restricted fields of view and in general are unlikely to be observing a potential neutrino-flaring source at the time such neutrinos are recorded. The use of neutrino-triggered alerts thus aims at increasing the availability of simultaneous multi-messenger data during potential neutrino flaring activity, which can increase the discovery potential and constrain the phenomenological interpretation of the high-energy emission of selected source classes (e.g. blazars). The requirements of a fast and stable online analysis of potential neutrino signals and its operation are presented, along with first results of the program operating between 14 March 2012 and 31 December 2015. 
IceCube Collaboration: M.G. Aartsen, K. Abraham, M. Ackermann,   J.Adams, J.A. Aguilar, M. Ahlers, M.Ahrens, D. Altmann, K. ...
hep-ex astro-ph.HE astro-ph.IM physics.ins-det