| 1. |
- Achterberg, A., et al.
(författare)
-
Five years of searches for point sources of astrophysical neutrinos with the AMANDA-II neutrino telescope
- 2007
-
Ingår i: Physical Review D. Particles, fields, gravitation, and cosmology. - 1550-7998. ; 75:10, s. 102001-
-
Tidskriftsartikel (refereegranskat)abstract
- We report the results of a five-year survey of the northern sky to search for point sources of high energy neutrinos. The search was performed on the data collected with the AMANDA-II neutrino telescope in the years 2000 to 2004, with a live time of 1001 days. The sample of selected events consists of 4282 upward going muon tracks with high reconstruction quality and an energy larger than about 100 GeV. We found no indication of point sources of neutrinos and set 90% confidence level flux upper limits for an all-sky search and also for a catalog of 32 selected sources. For the all-sky search, our average (over declination and right ascension) experimentally observed upper limit Phi0=((E/(1 TeV)))gamma·((d Phi)/dE) to a point source flux of muon and tau neutrino (detected as muons arising from taus) is Phinu[sub mu] + [overline nu ][sub mu]0+Phinu[sub tau] + [overline nu ][sub tau]0=11.1× 10-11 TeV-1 cm-2 s-1, in the energy range between 1.6 TeV and 2.5 PeV for a flavor ratio Phinu[sub mu] + [overline nu ][sub mu]0/Phinu[sub tau] + [overline nu ][sub tau]0=1 and assuming a spectral index gamma=2. It should be noticed that this is the first time we set upper limits to the flux of muon and tau neutrinos. In previous papers we provided muon neutrino upper limits only neglecting the sensitivity to a signal from tau neutrinos, which improves the limits by 10% to 16%. The value of the average upper limit presented in this work corresponds to twice the limit on the muon neutrino flux Phinu[sub mu] + [overline nu ][sub mu]0=5.5×10-11 TeV-1 cm-2 s-1. A stacking analysis for preselected active galactic nuclei and a search based on the angular separation of the events were also performed. We report the most stringent flux upper limits to date, including the results of a detailed assessment of systematic uncertainties.
|
|
| 2. |
- Abbasi, R., et al.
(författare)
-
SEARCH FOR HIGH-ENERGY MUON NEUTRINOS FROM THE "NAKED-EYE" GRB 080319B WITH THE IceCube NEUTRINO TELESCOPE
- 2009
-
Ingår i: Astrophysical Journal. - 0004-637X .- 1538-4357. ; 701:2, s. 1721-1731
-
Tidskriftsartikel (refereegranskat)abstract
- We report on a search with the IceCube detector for high-energy muon neutrinos from GRB 080319B, one of the brightest gamma-ray bursts (GRBs) ever observed. The fireball model predicts that a mean of 0.1 events should be detected by IceCube for a bulk Lorentz boost of the jet of 300. In both the direct on-time window of 66 s and an extended window of about 300 s around the GRB, no excess was found above background. The 90% CL upper limit on the number of track-like events from the GRB is 2.7, corresponding to a muon neutrino fluence limit of 9.5 x 10(-3) erg cm(-2) in the energy range between 120 TeV and 2.2 PeV, which contains 90% of the expected events.
|
|
| 3. |
|
|
| 4. |
|
|
| 5. |
- Burgess, Thomas, 1975-
(författare)
-
A Search for Solar Neutralino Dark Matter with the AMANDA-II Neutrino Telescope
- 2008
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- A relic density of Weakly Interacting Massive Particles (WIMPs) remaining from the Big Bang constitutes a promising solution to the Dark Matter problem. It is possible for such WIMPs to be trapped by and accumulate in gravitational potentials of massive dense objects such as the Sun. A perfect WIMP candidate appears in certain supersymmetric extensions to the Standard Model of particle physics, where the lightest supersymmetric particle is a neutralino which can be stable, massive and weakly interacting. The neutralinos may annihilate pair-wise and in these interactions neutrinos with energies ranging up to the neutralino mass can be indirectly produced. Hence, a possible population of dark matter neutralinos trapped in the Sun can give rise to an observable neutrino flux.The Antarctic Muon And Neutrino Detector Array, AMANDA, is a neutrino telescope that detects Cherenkov light emitted by charged particles created in neutrino interactions in the South Pole glacial ice sheet using an array of light detectors frozen into the deep ice. In this work data taken with the AMANDA-II detector during 2003 are analyzed to measure or put upper bounds on the flux of such neutrinos from the Sun. In the analysis detailed signal and background simulations are compared to measurements. Background rejection filters optimized for various neutralino models have been constructed. No excess above the background expected from neutrinos and muons created in cosmic ray interactions in the atmosphere was found. Instead 90% confidence upper limits have been set on the neutralino annihilation rate in the Sun and the muon flux induced by neutralino signal neutrinos.
|
|
