159 research outputs found
High-Energy Neutrino Scan of the Galactic Plane
No full textVarious searches for galactic high-energy neutrino sources with the neutrino telescopes IceCube and AMANDA are presented. The analysis uses data collected during 2008-2009 when IceCube was half completed. With AMANDA as an integrated part of the detector, the performance of IceCube below 10 TeV is improved significantly, opening new possibilities to improve the search for soft-spectra neutrino sources. The presented work provided important input to the design of DeepCore, the low-energy extension of IceCube, since it has established that the sensitivity to galactic neutrino sources can be enhanced by the collection of a higher number of neutrino candidates in the 100 GeV to 10 TeV range despite the higher background in this region. IceCube’s currently best soft-spectra upper limits for the Galactic Plane, for six galactic sources and for the star-forming “Cygnus” region have been obtained in this work. The sensitivity improved by at least a factor two with respect to the predecessor analysis. During the realization of this data analysis, IceCube nearly doubled its instrumented volume from 40 to 79 strings, including the advanced low-energy array DeepCore. The entire preparatory work for an All-Sky point source analysis with the nearly full detector has been performed. This thesis concludes with an outlook on the potential of the analysis of the IceCube 79-strings data
IceCube-Gen2: A Vision for the Future of Neutrino Astronomy in Antarctica
No full text20 pages, 12 figures. Address correspondence to: E. Blaufuss, F. Halzen, C. Kopper (Changed to add one missing author, no other changes from initial version.)20 pages, 12 figures. Address correspondence to: E. Blaufuss, F. Halzen, C. Kopper (Changed to add one missing author, no other changes from initial version.)20 pages, 12 figures. Address correspondence to: E. Blaufuss, F. Halzen, C. Kopper (Changed to add one missing author, no other changes from initial version.)The recent observation by the IceCube neutrino observatory of an astrophysical flux of neutrinos represents the "first light" in the nascent field of neutrino astronomy. The observed diffuse neutrino flux seems to suggest a much larger level of hadronic activity in the non-thermal universe than previously thought and suggests a rich discovery potential for a larger neutrino observatory. This document presents a vision for an substantial expansion of the current IceCube detector, IceCube-Gen2, including the aim of instrumenting a volume of clear glacial ice at the South Pole to deliver substantial increases in the astrophysical neutrino sample for all flavors. A detector of this size would have a rich physics program with the goal to resolve the sources of these astrophysical neutrinos, discover GZK neutrinos, and be a leading observatory in future multi-messenger astronomy programs
Monitoring der Stabilit\"{a}t des IceCube Detektors f\"{u}r neutrinogetriggerte Follow-up Beobachtungen
No full textSearch for Galactic Cosmic-Ray Accelerators with the Combined IceCube 40-strings and AMANDA Detector
No full textErratum: IceCube sensitivity for low-energy neutrinos from nearby supernovae(Astronomy and Astrophysics (2011) 535 : A109 (DOI: 10.1051/0004-6361/201117810))
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Searching for Soft Relativistic Jets in Core-collapse Supernovae with the IceCube Optical Follow-up Program
No full textContext. Transient neutrino sources such as gamma-ray bursts (GRBs) and supernovae (SNe) are hypothesized to emit bursts of high-energy neutrinos on a time-scale of ≲ 100 s. While GRB neutrinos would be produced in high relativistic jets, core-collapse SNe might host soft-relativistic jets, which become stalled in the outer layers of the progenitor star leading to an efficient production of high-energy neutrinos. Aims. To increase the sensitivity to these neutrinos and identify their sources, a low-threshold optical follow-up program for neutrino multiplets detected with the IceCube observatory has been implemented. Methods. If a neutrino multiplet, i.e. two or more neutrinos from the same direction within 100 s, is found by IceCube a trigger is sent to the Robotic Optical Transient Search Experiment, ROTSE. The 4 ROTSE telescopes immediately start an observation program of the corresponding region of the sky in order to detect an optical counterpart to the neutrino events. Results. No statistically significant excess in the rate of neutrino multiplets has been observed and furthermore no coincidence with an optical counterpart was found. Conclusions. The search allows, for the first time, to set stringent limits on current models predicting a high-energy neutrino flux from soft relativistic hadronic jets in core-collapse SNe. We conclude that a sub-population of SNe with typical Lorentz boost factor and jet energy of 10 and 3 × 10 51 erg, respectively, does not exceed 4.2% at 90% confidence. © 2012 ESO.0IceCube and ROTSE CollaborationsSCOPUS: ar.jinfo:eu-repo/semantics/publishe
Time-integrated searches for point-like sources of neutrinos with the 40-string IceCube detector
No full textWe present the results of time-integrated searches for astrophysical neutrino sources in both the northern and southern skies. Data were collected using the partially completed IceCube detector in the 40-string configuration recorded between 2008 April 5 and 2009 May 20, totaling 375.5 days livetime. An unbinned maximum likelihood ratio method is used to search for astrophysical signals. The data sample contains 36,900 events: 14,121 from the northern sky, mostly muons induced by atmospheric neutrinos, and 22,779 from the southern sky, mostly high-energy atmospheric muons. The analysis includes searches for individual point sources and stacked searches for sources in a common class, sometimes including a spatial extent. While this analysis is sensitive to TeV-PeV energy neutrinos in the northern sky, it is primarily sensitive to neutrinos with energy greater than about 1 PeV in the southern sky. No evidence for a signal is found in any of the searches. Limits are set for neutrino fluxes from astrophysical sources over the entire sky and compared to predictions. The sensitivity is at least a factor of two better than previous searches (depending on declination), with 90% confidence level muon neutrino flux upper limits being between E 2 dΦ/dE ∼ 2-200 × 10 -12 TeV cm-2 s-1 in the northern sky and between 3-700 × 10-12 TeV cm-2 s-1 in the southern sky. The stacked source searches provide the best limits to specific source classes. The full IceCube detector is expected to improve the sensitivity to dΦ/dEE ∝ -2 sources by another factor of two in the first year of operation. © 2011. The American Astronomical Society. All rights reserved.0SCOPUS: ar.jinfo:eu-repo/semantics/publishe
Search for relativistic magnetic monopoles with IceCube
No full textArticle part of CHORUS PilotWe present the first results in the search for relativistic magnetic monopoles with the IceCube detector, a subsurface neutrino telescope located in the South Polar ice cap containing a volume of 1 km³. This analysis searches data taken on the partially completed detector during 2007 when roughly 0.2 km³ of ice was instrumented. The lack of candidate events leads to an upper limit on the flux of relativistic magnetic monopoles of Φ(90%C.L.)∼3×10⁻¹⁸ cm⁻² sr⁻¹ s⁻¹ for β≥0.8. This is a factor of 4 improvement over the previous best experimental flux limits up to a Lorentz boost γ below 10⁷. This result is then interpreted for a wide range of mass and kinetic energy values.R. Abbasi ... G. C. Hill ... et al. (IceCube Collaboration
First search for atmospheric and extraterrestrial neutrino-induced cascades with the IceCube detector
No full textWe report on the first search for atmospheric and for diffuse astrophysical neutrino-induced showers (cascades) in the IceCube detector using 257 days of data collected in the year 2007-2008 with 22 strings active. A total of 14 events with energies above 16TeV remained after event selections in the diffuse analysis, with an expected total background contribution of 8.3±3.6. At 90% confidence we set an upper limit of E2Φ90%CL<3. 6×10-7GeV•cm-2•s-1•sr -1 on the diffuse flux of neutrinos of all flavors in the energy range between 24TeV and 6.6PeV assuming that ΦE-2 and the flavor composition of the νeνμντ flux is 111 at the Earth. The atmospheric neutrino analysis was optimized for lower energies. A total of 12 events were observed with energies above 5TeV. The observed number of events is consistent with the expected background, within the uncertainties. © 2011 American Physical Society.0SCOPUS: ar.jinfo:eu-repo/semantics/publishe
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