Detection and localization of very high energy neutrinos by a passive underwater acoustic telescope

摘要

The observation of the Universe requires the using of more and more performing Telescopes. In particular, an underwater telescope has been set off Toulon, named Antares for Astronomy with a Neutrino Telescope and Abyss RESearch, composed by vertical hydrophones lines (see Fig. 1). It is used for the detection and the estimation of direction of arrival of very high energy neutrinos. Indeed, very high energy neutrinos can be detected thanks to a shower they produce in the sea water. This shower is the source of a very short acoustic signal, called Antares signal. After having presented a non standard modelization of the Antares signal, we propose an ad hoc detection scheme based upon a so called 'Extented Stochastic Matched Filter' and 'Constrainted Stochastic Matched Filter'. The estimation of the Time Difference of Arrival (TDOA), between signal received by two hydrophones is performed by a simple correlator on filtered signals. The set of TDOA estimates are used as measurements needed for the estimation of the direction of shower. The paper is outlined as follows: In section I, we introduce the so called acoustic Antares signal. Section II is devoted to the detection tests. In section III, the Difference Time of Arrival estimation is presented together with some results. The trajectory estimation principle is given in section IV. Finally, we conclude.