Search for neutrino emission of gamma-ray flaring blazars with the ANTARES telescope

Abstract

The ANTARES telescope is well suited to detect neutrinos produced in astrophysical transient sources as it can observe a full hemisphere of the sky at all times with a high duty cycle. The background and point source sensitivity can be drastically reduced by selecting a narrow time window around the assumed neutrino production period. Radio-loud active galactic nuclei with their jets pointing almost directly towards the observer, the so- called blazars, are particularly attractive potential neutrino point sources, since they are among the most likely sources of the observed ultra high energy cosmic rays and therefore, neutrinos and gamma-rays may be produced in hadronic interactions with the surrounding medium. The gamma-ray light curves of blazars measured by the LAT instrument on-board the Fermi satellite reveal important time variability information. A strong correlation between the gamma-ray and the neutrino fluxes is expected in this scenario. An unbinned method based on the minimization of a likelihood ratio was applied to a subsample data collected in 2008 (61 days live time). By looking for neutrinos detected in the high state periods of the AGN light curve, the sensitivity to these sources has been improved by about a factor 2 with respect to a standard time-integrated point source search. First results on the search for ten bright and variable Fermi sources are presented.