The search for transient astrophysical neutrino emission with IceCube-DeepCore

MG Aartsen, K Abraham, M Ackermann… - The Astrophysical …, 2016 - iopscience.iop.org
MG Aartsen, K Abraham, M Ackermann, J Adams, JA Aguilar, M Ahlers, M Ahrens…
The Astrophysical Journal, 2016iopscience.iop.org
The nascent field of high-energy neutrino astronomy opens the possibility of answering
several open questions in astrophysics due in large part to the neutrino's ability to escape
the densest regions of astrophysical environments. Specifically, the detection of transient
astrophysical neutrino sources will help shed light on the acceleration mechanisms at work
in some of the most energetic phenomena in the universe such as gamma-ray bursts
(GRBs), supernovae, and active galactic nuclei (AGNs). Previous attempts to detect such …
The nascent field of high-energy neutrino astronomy opens the possibility of answering several open questions in astrophysics due in large part to the neutrino’s ability to escape the densest regions of astrophysical environments. Specifically, the detection of transient astrophysical neutrino sources will help shed light on the acceleration mechanisms at work in some of the most energetic phenomena in the universe such as gamma-ray bursts (GRBs), supernovae, and active galactic nuclei (AGNs). Previous attempts to detect such sources with the IceCube Neutrino Observatory (Achterberg et al. 2006) are most sensitive to neutrino fluxes above 1 TeV with poor sensitivity below 100GeV. Searches for astrophysical sources at lower energies (1–100 GeV) have been performed by Super-Kamiokande (Thrane et al. 2009), but the detector’s 50 kton instrumented volume limits its sensitivity to astrophysical neutrino fluxes. A newly developed 30–300 GeV muon-neutrino sample collected by IceCube and its low-energy extension DeepCore (Abbasi et al. 2012b) enhances IceCube’s sensitivity in this underexplored energy range. In this paper we will present the results of a search for transient neutrino emission in this GeV-scale neutrino sample. The detection of astrophysical neutrino sources is a primary design goal of the IceCube Neutrino Observatory (Achterberg et al. 2006). Located at the geographic South Pole, IceCube utilizes the clear Antarctic glacial ice cap as a detection medium for the Cerenkov light produced by secondary products of neutrino interactions. The detector consists of 5160 digital optical modules (DOMs) distributed among 86 cables or “strings” to form a 1 km3 instrumented volume. These DOMs house photomultiplier tubes (PMTs), to detect Cerenkov photons, as well as digitizing electronics for initial processing of the PMT data (Abbasi et al. 2009). A centrally located region of denser instrumentation featuring DOMs with more sensitive PMTs comprises the DeepCore sub-array. This extension to the IceCube array enhances the detector’s response to lower energy neutrino events. Typical searches for astrophysical sources with IceCube make use of a sample primarily composed of an irreducible
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