On the selection of AGN neutrino source candidates for a source stacking analysis with neutrino telescopes

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 models, as briefly reviewed in this paper. The source stacking search for neutrinos from generic AGN classes is illustrated using the data collected by the AMANDA-II high energy neutrino detector during the year 2000. No significant excess for any of the suggested groups was found.Comment: 43 pages, 12 figures, accepted by Astroparticle Physic

A search for Gamma Ray Burst Neutrinos in AMANDA

To date, no neutrinos with energies in or above the GeV range have been identified from astrophysical objects. The aim of the two analyses described in this dissertation is to observe high-energy muon neutrinos from Gamma Ray Bursts (GRBs). GRBs are distant sources, which were discovered by satellites recording their flashes of high-energy electromagnetic radiation. In some cases, the gamma-ray flashes are followed by lower energy radiation. GRBs are observed to have a well localized position and a short duration. This allows us to reduce the background in searching the data of the AMANDA/IceCube detector for a possible signal. As no detection of those highly energetic neutrinos has succeeded so far, we aim to analyze our data in a rather unbiased way and limit the dependence on theoretical modelling of the GRB engine. To this end we filter the data using parameters which depend only weakly on the neutrino energy spectrum (unlike a previous analysis in Achterberg et al. (2007)). Besides this, we allow for a possible time di erence between the arrival time of the prompt photon emission and the neutrino signal: our analyses are sensitive to signals arriving within one hour of the satellite trigger time (whereas previous analyses followed an approach which is only sensitive for signals within ten minutes centered around the arrival of the prompt -s (Achterberg et al. 2008)). The two separate analyses presented here di er in one important aspect: in the analysis of the specific burst GRB080319B we analyze the data of one single GRB event for the presence of neutrinos from this GRB. The central assumption is that this ”brightest GRB observed to date” might produce a high-energy neutrino flux which is significantly higher than the average GRB neutrino flux. (This approach was also followed in the analysis of the data of GRB030329 (Stamatikos & et al. 2005).) The second analysis we present is based on stacking the data of multiple GRBs (with average properties) to cope with low fluxes. The directional and timing information of the GRBs used in our analyses is taken from these sources. As we do not use complex spectral information and the required resolution on time and location is moderate, we can incorporate the information of various experiments. Most of the GRBs in our sample were observed by the Swift satellite, others by Fermi, Integral, SuperAgile or IPN (the InterPlanetary Network). In chapter 2 we briefly outline the leading GRB models and discuss to what extent our analyses depend on model assumptions. In chapter 3 we give the characteristics of our detector. Subsequently in chapter 4 we provide all details on how we calibrate the detector and process the data. The method we will use to assess the significance of our observations is outlined in chapter 5. The details of the analyses themselves are given in chapters 6 and 7. We discuss the results in chapter 8

The search for muon neutrinos from northern hemisphere gamma-ray bursts with AMANDA

We present the results of the analysis of neutrino observations by the Antarctic Muon and Neutrino Detector Array (AMANDA) correlated with photon observations of more than 400 gamma-ray bursts (GRBs) in the northern hemisphere from 1997 to 2003. During this time period, AMANDA's effective collection area for muon neutrinos was larger than that of any other existing detector. After the application of various selection criteria to our data, we expect ~1 neutrino event an

Limits on the muon flux from neutralino annihilations at the center of the Earth with AMANDA

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

Erratum: Multiyear search for a diffuse flux of muon neutrinos with AMANDA-II [Phys. Rev. D 76, 042008 (2007)]

A search for TeV-PeV muon neutrinos with AMANDA-II data collected between 2000 and 2003 established an upper limit of E2Φ90%C:L: <7:4 x 10-8 GeV cm-2s-1sr-1 on the diffuse flux of extraterrestrial muon neutrinos with a Φ E-2 spectrum between 16 TeV and 2.5 PeV. The upper limit calculation correctly included event simulations and remains as stated

Multiyear search for a diffuse flux of muon neutrinos with AMANDA-II

A search for TeV-PeV muon neutrinos from unresolved sources was performed on AMANDA-II data collected between 2000 and 2003 with an equivalent live time of 807 days. This diffuse analysis sought to find an extraterrestrial neutrino flux from sources with nonthermal components. The signal is expected to have a harder spectrum than the atmospheric muon and neutrino backgrounds. Since no excess of events was seen in the data over the expected background, an upper limit of E2Φ90%C.L

Search for neutrino-induced cascades from gamma-ray bursts with AMANDA

Using the neutrino telescope AMANDA-II, we have conducted two analyses searching for neutrino-induced cascades from gamma-ray bursts. No evidence of astrophysical neutrinos was found, and limits are presented for several models. We also present neutrino effective areas which allow the calculation of limits for any neutrino production model. The first analysis looked for a statistical excess of events within a sliding window of 1 or 100 seconds (for short and long burst classes, respectively) during the years 2001-2003. The resulting upper limit on the diffuse flux normalization times E^2 for the Waxman-Bahcall model at 1 PeV is 1.6 x 10^-6 GeV cm^-2 s^-1 sr^-1 (a factor of 120 above the theoretical prediction). For this search 90% of the neutrinos would fall in the energy range 50 TeV to 7 PeV. The second analysis looked for neutrino-induced cascades in coincidence with 73 bursts detected by BATSE in the year 2000. The resulting upper limit on the diffuse flux normalization times E^2, also at 1 PeV, is 1.5 x 10^-6 GeV cm^-2 s^-1 sr^-1 (a factor of 110 above the theoretical prediction) for the same energy range. The neutrino-induced cascade channel is complementary to the up-going muon channel. We comment on its advantages for searches of neutrinos from GRBs and its future use with IceCube