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Register a new userExpected discovery potential and sensitivity of the ANTARES neutrino telescope to neutrino point-like sources
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Added by
Juan Antonio Aguilar S\\'anchez Mr.
Publication date
2007
fields
Physics
and research's language is
English
Authors
J.A. Aguilar
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The ANTARES telescope is being built in the Mediterranean Sea. The detector consists of a 3D array of photomultipliers (PMTs) that detects the Cherenkov light induced by the muons produced in neutrino interactions. Other signatures can also be detected. Since the neutrino fluxes from point-like sources are expected to be small, it is of the utmost importance to take advantage of the ANTARES pointing accuracy (angular resolution better than 0.3 degrees for muon events above 10 TeV) to disentangle a possible signal from the unavoidable atmospheric neutrino background. In order to distinguish an excess of neutrino events from the background, several searching algorithms have been developed within the ANTARES collaboration. In this contribution, the discovery potential and sensitivity to point-like sources of the ANTARES neutrino telescope are presented.
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KM3NeT will be a network of deep-sea neutrino telescopes in the Mediterranean Sea. The KM3NeT/ARCA detector, to be installed at the Capo Passero site (Italy), is optimised for the detection of high-energy neutrinos of cosmic origin. Thanks to its geographical location on the Northern hemisphere, KM3NeT/ARCA can observe upgoing neutrinos from most of the Galactic Plane, including the Galactic Centre. Given its effective area and excellent pointing resolution, KM3NeT/ARCA will measure or significantly constrain the neutrino flux from potential astrophysical neutrino sources. At the same time, it will test flux predictions based on gamma-ray measurements and the assumption that the gamma-ray flux is of hadronic origin. Assuming this scenario, discovery potentials and sensitivities for a selected list of Galactic sources and to generic point sources with an $E^{-2}$ spectrum are presented. These spectra are assumed to be time independent. The results indicate that an observation with $3sigma$ significance is possible in about six years of operation for the most intense sources, such as Supernovae Remnants RX,J1713.7-3946 and Vela Jr. If no signal will be found during this time, the fraction of the gamma-ray flux coming from hadronic processes can be constrained to be below 50% for these two objects.
A search for cosmic neutrino sources using six years of data collected by the ANTARES neutrino telescope has been performed. Clusters of muon neutrinos over the expected atmospheric background have been looked for. No clear signal has been found. The most signal-like accumulation of events is located at equatorial coordinates RA=$-$46.8$^{circ}$ and Dec=$-$64.9$^{circ}$ and corresponds to a 2.2$sigma$ background fluctuation. In addition, upper limits on the flux normalization of an E$^{-2}$ muon neutrino energy spectrum have been set for 50 pre-selected astrophysical objects. Finally, motivated by an accumulation of 7 events relatively close to the Galactic Centre in the recently reported neutrino sample of the IceCube telescope, a search for point sources in a broad region around this accumulation has been carried out. No indication of a neutrino signal has been found in the ANTARES data and upper limits on the flux normalization of an E$^{-2}$ energy spectrum of neutrinos from point sources in that region have been set. The 90% confidence level upper limits on the muon neutrino flux normalization vary between 3.5 and 5.1$times$10$^{-8}$ GeV$,$cm$^{-2}$s$^{-1}$, depending on the exact location of the source.
A search for cosmic neutrino sources using the data collected with the ANTARES neutrino telescope between early 2007 and the end of 2015 is performed. For the first time, all neutrino interactions --charged and neutral current interactions of all flavours-- are considered in a search for point-like sources with the ANTARES detector. In previous analyses, only muon neutrino charged current interactions were used. This is achieved by using a novel reconstruction algorithm for shower-like events in addition to the standard muon track reconstruction. The shower channel contributes about 23% of all signal events for an $E^{-2}$ energy spectrum. No significant excess over background is found. The most signal-like cluster of events is located at $(alpha,delta) = (343.8^circ, 23.5^circ)$ with a significance of $1.9sigma$. The neutrino flux sensitivity of the search is about $E^2 dvarPhi/dE = 6cdot10^{-9} GeV cm^{-2} s^{-1}$ for declinations from $-90^circ$ up to $-42^circ$, and below $10^{-8} GeV cm^{-2} s^{-1}$ for declinations up to $5^{circ}$. The directions of 106 source candidates and of 13 muon track events from the IceCube HESE sample are investigated for a possible neutrino signal and upper limits on the signal flux are determined.
A novel method to analyse the spatial distribution of neutrino candidates recorded with the ANTARES neutrino telescope is introduced, searching for an excess of neutrinos in a region of arbitrary size and shape from any direction in the sky. Techniques originating from the domains of machine learning, pattern recognition and image processing are used to purify the sample of neutrino candidates and for the analysis of the obtained skymap. In contrast to a dedicated search for a specific neutrino emission model, this approach is sensitive to a wide range of possible morphologies of potential sources of high-energy neutrino emission. The application of these methods to ANTARES data yields a large-scale excess with a post-trial significance of 2.5$sigma$. Applied to public data from IceCube in its IC40 configuration, an excess consistent with the results from ANTARES is observed with a post-trial significance of 2.1$sigma$.
The ANTARES underwater neutrino telescope, at a depth of 2475 m in the Mediterranean Sea, near Toulon, is taking data in its final configuration of 12 detection lines. Each line is equipped with 75 photomultipliers (PMT) housed in glass pressure spheres arranged in 25 triplets at depths between 100 and 450 m above the sea floor. The PMTs look down at 45^o to have better sensitivity to the Cherenkov light from upgoing muons produced in the interactions of high energy neutrinos traversing the Earth. Such neutrinos may arrive from a variety of astrophysical sources, though the majority are atmospheric neutrinos. The data from 5 lines in operation in 2007 yielded a sufficient number of downgoing muons with which to study the detector performances, the vertical muon intensity and reconstruct the first upgoing neutrino induced muons.
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