0000000000237015
AUTHOR
Ph. Olbrechts
showing 21 related works from this author
Limits to the muon flux from WIMP annihilation in the center of the Earth with the AMANDA detector
2002
A search for nearly vertical up-going muon-neutrinos from neutralino annihilations in the center of the Earth has been performed with the AMANDA-B10 neutrino detector. The data sample collected in 130.1 days of live-time in 1997, ~10^9 events, has been analyzed for this search. No excess over the expected atmospheric neutrino background is oberved. An upper limit at 90% confidence level on the annihilation rate of neutralinos in the center of the Earth is obtained as a function of the neutralino mass in the range 100 GeV-5000 GeV, as well as the corresponding muon flux limit.
Calibration and survey of AMANDA with the SPASE detectors
2004
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. © 2003 Elsevier B.V. All rights reserved.
Results from the AMANDA telescope
2003
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.
Search for extraterrestrial point sources of high energy neutrinos with AMANDA-II using data collected in 2000-2002
2005
The results of a search for point sources of high energy neutrinos in the northern hemisphere using data collected by AMANDA-II in the years 2000, 2001 and 2002 are presented. In particular, a comparison with the single-year result previously published shows that the sensitivity was improved by a factor of 2.2. The muon neutrino flux upper limits on selected candidate sources, corresponding to an E^{-2} neutrino energy spectrum, are included. Sky grids were used to search for possible excesses above the background of cosmic ray induced atmospheric neutrinos. This search reveals no statistically significant excess for the three years considered.
Limits on the high-energy gamma and neutrino fluxes from the SGR 1806-20 giant flare of 27 December 2004 with the AMANDA-II detector.
2006
On December 27th 2004, a giant gamma flare from the Soft Gamma-ray Repeater 1806-20 saturated many satellite gamma-ray detectors. This event was by more than two orders of magnitude the brightest cosmic transient ever observed. If the gamma emission extends up to TeV energies with a hard power law energy spectrum, photo-produced muons could be observed in surface and underground arrays. Moreover, high-energy neutrinos could have been produced during the SGR giant flare if there were substantial baryonic outflow from the magnetar. These high-energy neutrinos would have also produced muons in an underground array. AMANDA-II was used to search for downgoing muons indicative of high-energy gamm…
First year performance of the IceCube neutrino telescope
2006
The first sensors of the IceCube neutrino observatory were deployed at the South Pole during the austral summer of 2004-2005 and have been producing data since February 2005. One string of 60 sensors buried in the ice and a surface array of eight ice Cherenkov tanks took data until December 2005 when deployment of the next set of strings and tanks began. We have analyzed these data, demonstrating that the performance of the system meets or exceeds design requirements. Times are determined across the whole array to a relative precision of better than 3 ns, allowing reconstruction of muon tracks and light bursts in the ice, of air-showers in the surface array and of events seen in coincidence…
Search for Neutrino-Induced Cascades with AMANDA
2004
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 $\Phi \propto E^{-2}$ which consists of an equal mix of all flavors, is limited to $E^2 \Phi(E)=8.6 x 10^{-7} GeV/(cm^{2} s sr)$ 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 t…
Flux limits on ultra high energy neutrinos with AMANDA-B10
2005
Abstract Data taken during 1997 with the AMANDA-B10 detector are searched for a diffuse flux of neutrinos of all flavors with energies above 10 16 eV. At these energies the Earth is opaque to neutrinos, and thus neutrino induced events are concentrated at the horizon. The background are large muon bundles from down-going atmospheric air shower events. No excess events above the background expectation are observed and a neutrino flux following E −2 , with an equal mix of all flavors, is limited to E 2 Φ (10 15 eV E 18 eV) ⩽ 0.99 × 10 −6 GeV cm −2 s −1 sr −1 at 90% confidence level. This is the most restrictive experimental bound placed by any neutrino detector at these energies. Bound…
NEUTRINO ASTRONOMY AND COSMIC RAYS AT THE SOUTH POLE: LATEST RESULTS FROM AMANDA AND PERSPECTIVES FOR ICECUBE
2005
The AMANDA neutrino telescope has been in operation at the South Pole since 1996. The present final array configuration, operational since 2000, consists of 677 photomultiplier tubes arranged in 19 strings, buried at depths between 1500 and 2000 m in the ice. The most recent results on a multi-year search for point sources of neutrinos will be shown. The study of events triggered in coincidence with the surface array SPASE and AMANDA provided a result on cosmic ray composition. Expected improvements from IceCube/IceTop will also be discussed.
Recent results from AMANDA II
2003
Abstract We present new data taken with the AMANDA-II neutrino telescope array. The AMANDA-II upgrade was completed at the beginning of 2000. It significantly extends the sensitivity of the 10-string AMANDA-B10 detector to high- and ultrahigh-energy neutrino fluxes into regions of interest for probing current astrophysical models which remain unexplored by other experiments.
Sensitivity of the IceCube detector to astrophysical sources of high energy muon neutrinos
2003
We present the 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 sources such as active galaxies and gamma-ray bursts. 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 emissions, including an assessment of the sensitivity to neutrinos detected in coincidence with gamma-ray burst observatio…
Optical properties of deep glacial ice at the South Pole
2006
We have remotely mapped optical scattering and absorption in glacial ice at the South Pole for wavelengths between 313 and 560 nm and depths between 1100 and 2350 m. We used pulsed and continuous light sources embedded with the AMANDA neutrino telescope, an array of more than six hundred photomultiplier tubes buried deep in the ice. At depths greater than 1300 m, both the scattering coefficient and absorptivity follow vertical variations in concentration of dust impurities, which are seen in ice cores from other Antarctic sites and which track climatological changes. The scattering coefficient varies by a factor of seven, and absorptivity (for wavelengths less than ∼450 nm) varies by a fact…
Measurement of the cosmic ray composition at the knee with the SPASE-2/AMANDA-B10 detectors
2004
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 throug…
Limits on diffuse fluxes of high energy extraterrestrial neutrinos with the AMANDA-B10 detector
2003
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, as predicted from, e.g., the sum of all active galaxies in the universe. This search yielded no excess events above those expected from the background atmospheric neutrinos, leading to upper limits on the extraterrestrial neutrino flux. For an assumed E^-2 spectrum, a 90% classical confidence level upper limit has been placed at a level E^2 Phi(E) = 8.4 x 10^-7 GeV cm^-2 s^-1 sr^-1 (for a predominant neutrino energy range 6-1000 TeV) which is the most restrictive bound placed by any neutrino detector. When specific predicted spectral…
Limits on the muon flux from neutralino annihilations at the center of the Earth with AMANDA
2006
A search has been performed for nearly vertically upgoing neutrino-induced muons with the Antarctic Muon And Neutrino Detector Array (AMANDA), using data taken over the three year period 1997–99. No excess above the expected atmospheric neutrino background has been found. Upper limits at 90% confidence level have been set on the annihilation rate of neutralinos at the center of the Earth, as well as on the muon flux at AMANDA induced by neutrinos created by the annihilation products.
Observation of high energy atmospheric neutrinos with the Antarctic muon and neutrino detector array
2002
The Antarctic Muon and Neutrino Detector Array (AMANDA) began collecting data with ten strings in 1997. Results from the first year of operation are presented. Neutrinos coming through the Earth from the Northern Hemisphere are identified by secondary muons moving upward through the array. Cosmic rays in the atmosphere generate a background of downward moving muons, which are about 10^6 times more abundant than the upward moving muons. Over 130 days of exposure, we observed a total of about 300 neutrino events. In the same period, a background of 1.05*10^9 cosmic ray muon events was recorded. The observed neutrino flux is consistent with atmospheric neutrino predictions. Monte Carlo simulat…
IceCube: A multipurpose neutrino telescope
2008
IceCube is a new high-energy neutrino telescope which will be coming online in the near future. IceCube will be capable of measuring fluxes of all three flavors of neutrino, and its peak neutrino energy sensitivity will be in the TeV–PeV range. Here, after a brief description of the detector, we describe its anticipated performance with a selection of physics topics: supernovae, extraterrestrial diffuse and point sources of neutrinos, gamma-ray bursts, neutrinos from WIMP annihilation, and cosmic ray composition.
On the selection of AGN neutrino source candidates for a source stacking analysis with neutrino telescopes
2006
The sensitivity of a search for sources of TeV neutrinos can be improved by grouping potential sources together into generic classes in a procedure that is known as source stacking. In this paper, we define catalogs of Active Galactic Nuclei (AGN) and use them to perform a source stacking analysis. The grouping of AGN into classes is done in two steps: first, AGN classes are defined, then, sources to be stacked are selected assuming that a potential neutrino flux is linearly correlated with the photon luminosity in a certain energy band (radio, IR, optical, keV, GeV, TeV). Lacking any secure detailed knowledge on neutrino production in AGN, this correlation is motivated by hadronic AGN mode…
Limits to the muon flux from neutralino annihilations in the Sun with the AMANDA detector
2005
A search for an excess of muon-neutrinos from neutralino annihilations in the Sun has been performed with the AMANDA-II neutrino detector using data collected in 143.7 days of live-time in 2001. No excess over the expected atmospheric neutrino background has been observed. An upper limit at 90% confidence level has been obtained on the annihilation rate of captured neutralinos in the Sun, as well as the corresponding muon flux limit at the Earth, both as functions of the neutralino mass in the range 100 GeV-5000 GeV.
Muon track reconstruction and data selection techniques in AMANDA
2004
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 1500m and 2000m. 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 r…
Status of the IceCube Neutrino Observatory
2004
Abstract The IceCube neutrino telescope, to be constructed near the Antarctic South Pole, represents the next generation of neutrino telescope. Its large 1 km3 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.