Search for sources of high-energy neutrons with four years of data from the IceTop detector

• Published in: The Astrophysical Journal
• Main Authors: Aartsen, M.G., Abraham, K., Ackermann, M., Adams, J., Aguilar, J.A., Ahlers, M., Ahrens, M., Altmann, D., Andeen, K., Anderson, T., Ansseau, I., Anton, G., Archinger, M., Argüelles, C., Auffenberg, J., Axani, S., Bai, X., Barwick, S.W., Baum, V., Bay, R.
• Format: Article in Journal/Newspaper
• Language: English
• Published: IOP Publishing 2016
• Subjects: Astroparticle physics; cosmic rays; methods: data analysis; Antarctic; The Antarctic; South Pole; Antarc*; Ice Sheet; South pole
• Online Access: http://hdl.handle.net/2440/106105; https://doi.org/10.3847/0004-637X/830/2/129

IceTop is an air-shower array located on the Antarctic ice sheet at the geographic South Pole. IceTop can detect an astrophysical flux of neutrons from Galactic sources as an excess of cosmic-ray air showers arriving from the source direction. Neutrons are undeflected by the Galactic magnetic field and can typically travel 10 (E/PeV) pc before decay. Two searches are performed using 4 yr of the IceTop data set to look for a statistically significant excess of events with energies above 10 PeV (10¹⁶ eV) arriving within a small solid angle. The all-sky search method covers from −90° to approximately −50° in declination. No significant excess is found. A targeted search is also performed, looking for significant correlation with candidate sources in different target sets. This search uses a higher-energy cut (100 PeV) since most target objects lie beyond 1 kpc. The target sets include pulsars with confirmed TeV energy photon fluxes and high-mass X-ray binaries. No significant correlation is found for any target set. Flux upper limits are determined for both searches, which can constrain Galactic neutron sources and production scenarios. M.G. Aartsen … S. Robertson … A. Wallace … B.J. Whelan … [et al.] (The ICECUBE Collaboration)