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.
Data from the AMANDA-B10 detector taken during the austral winter of 1997 have been searched for a diffuse flux of high energy extraterrestrial muon neutrinos. This search yielded no excess events ...above those expected from background atmospheric neutrinos, leading to upper limits on the extraterrestrial neutrino flux measured at the earth. For an assumed E-2 spectrum, a 90% classical confidence level upper limit has been placed at a level E2Phi(E)=8.4 x 10(-7) cm(-2) s(-1) sr(-1) GeV (for a predominant neutrino energy range 6-1000 TeV), which is the most restrictive bound placed by any neutrino detector. Some specific predicted model spectra are excluded. Interpreting these limits in terms of the flux from a cosmological distributions of sources requires the incorporation of neutrino oscillations, typically weakening the limits by a factor of 2.
We report on a search for electro-magnetic and/or hadronic showers (cascades) induced by high-energy neutrinos in the data collected with the AMANDA II detector during the year 2000. The observed ...event rates are consistent with the expectations for atmospheric neutrinos and muons. We place upper limits on a diffuse flux of extraterrestrial electron, tau and muon neutrinos. A flux of neutrinos with a spectrum Φ∝E−2 which consists of an equal mix of all flavors, is limited to E2Φ(E)=8.6×10−7 GeVcm−2s−1sr−1 at a 90% confidence level for a neutrino energy range 50 TeV to 5 PeV. We present bounds for specific extraterrestrial neutrino flux predictions. Several of these models are ruled out.
The mass composition of high-energy cosmic rays at energies above 1015 eV can provide crucial information for the understanding of their origin. Air showers were measured simultaneously with the ...SPASE-2 air shower array and the AMANDA-B10 Cherenkov telescope at the South Pole. This combination has the advantage to sample almost all high-energy shower muons and is thus a new approach to the determination of the cosmic ray composition. The change in the cosmic ray mass composition was measured versus existing data from direct measurements at low energies. Our data show an increase of the mean log atomic mass 〈lnA〉 by about 0.8 between 500 TeV and 5 PeV. This trend of an increasing mass through the “knee” region is robust against a variety of systematic effects.
Calibration and survey of AMANDA with the SPASE detectors Ahrens, J; Bai, X; Barwick, S.W ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
04/2004, Letnik:
522, Številka:
3
Journal Article
Recenzirano
Odprti dostop
We report on the analysis of air showers observed in coincidence by the Antarctic Muon and Neutrino detector array (AMANDA-B10) and the South Pole Air Shower Experiment (SPASE-1 and SPASE-2). We ...discuss the use of coincident events for calibration and survey of the deep AMANDA detector as well as the response of AMANDA to muon bundles. This analysis uses data taken during 1997 when both SPASE-1 and SPASE-2 were in operation to provide a stereo view of AMANDA.
We present results of a Monte Carlo study of the sensitivity of the planned IceCube detector to predicted fluxes of muon neutrinos at TeV to PeV energies. A complete simulation of the detector and ...data analysis is used to study the detector’s capability to search for muon neutrinos from potential sources such as active galaxies and gamma-ray bursts (GRBs). We study the effective area and the angular resolution of the detector as a function of muon energy and angle of incidence. We present detailed calculations of the sensitivity of the detector to both diffuse and pointlike neutrino fluxes, including an assessment of the sensitivity to neutrinos detected in coincidence with GRB observations. After three years of data taking, IceCube will be able to detect a point-source flux of
E
ν
2×d
N
ν
/d
E
ν
=7×10
−9 cm
−2
s
−1
GeV at a 5
σ significance, or, in the absence of a signal, place a 90% c.l. limit at a level of
E
ν
2×d
N
ν
/d
E
ν
=2×10
−9 cm
−2
s
−1
GeV. A diffuse
E
−2 flux would be detectable at a minimum strength of
E
ν
2×d
N
ν
/d
E
ν
=10
−8 cm
−2
s
−1
sr
−1
GeV. A GRB model following the formulation of Waxman and Bahcall would result in a 5
σ effect after the observation of 200 bursts in coincidence with satellite observations of the gamma rays.
Muon track reconstruction and data selection techniques in AMANDA Ahrens, J.; Bai, X.; Bay, R. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
05/2004, Letnik:
524, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The Antarctic Muon And Neutrino Detector
Array (AMANDA) is a high-energy neutrino telescope operating at the geographic South Pole. It is a lattice of photo-multiplier tubes buried deep in the polar ...ice between 1500 and
2000
m
. The primary goal of this detector is to discover astrophysical sources of high-energy neutrinos. A high-energy muon neutrino coming through the earth from the Northern Hemisphere can be identified by the secondary muon moving upward through the detector.
The muon tracks are reconstructed with a maximum likelihood method. It models the arrival times and amplitudes of Cherenkov photons registered by the photo-multipliers. This paper describes the different methods of reconstruction, which have been successfully implemented within
AMANDA. Strategies for optimizing the reconstruction performance and rejecting background are presented. For a typical analysis procedure the direction of tracks are reconstructed with about 2° accuracy.
The IceCube neutrino telescope, to be constructed near the Antarctic South Pole, represents the next generation of neutrino telescope. Its large 1 km
3 size will make it uniquely sensitive to the ...detection of neutrinos from astrophysical sources. The current design of the detector is presented. The basic performance of the detector and its ability to search for neutrinos from various astrophysical sources has been studied using detailed simulations and is discussed.
We present results from the AMANDA high energy neutrino telescope located at the South Pole. They include measurements of the atmospheric neutrino flux, search for UHE point sources, and diffuse ...sources producing electromagnetic/hadronic showers at the detector or close to it.
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