uu.seUppsala University Publications
Change search
ReferencesLink to record
Permanent link

Direct link
Lowering Icecube'S Energy Threshold For Point Source Searches In The Southern Sky
Univ Adelaide, Dept Phys, Adelaide, SA 5005, Australia..
Tech Univ Munich, Dept Phys, D-85748 Garching, Germany..
DESY, D-15735 Zeuthen, Germany..
Univ Canterbury, Dept Phys & Astron, Private Bag 4800, Christchurch 1, New Zealand..
Show others and affiliations
2016 (English)In: Astrophysical Journal Letters, ISSN 2041-8205, E-ISSN 2041-8213, Vol. 824, no 2, L28Article in journal (Refereed) PublishedText
Abstract [en]

Observation of a point source of astrophysical neutrinos would be a "smoking gun" signature of a cosmic-ray accelerator. While IceCube has recently discovered a diffuse flux of astrophysical neutrinos, no localized point source has been observed. Previous IceCube searches for point sources in the southern sky were restricted by either an energy threshold above a few hundred TeV or poor neutrino angular resolution. Here we present a search for southern sky point sources with greatly improved sensitivities to neutrinos with energies below 100 TeV. By selecting charged-current nu(mu) interacting inside the detector, we reduce the atmospheric background while retaining efficiency for astrophysical neutrino-induced events reconstructed with sub-degree angular resolution. The new event sample covers three years of detector data and leads to a factor of 10 improvement in sensitivity to point sources emitting below 100 TeV in the southern sky. No statistically significant evidence of point sources was found, and upper limits are set on neutrino emission from individual sources. A posteriori analysis of the highest-energy (similar to 100 TeV) starting event in the sample found that this event alone represents a 2.8 sigma deviation from the hypothesis that the data consists only of atmospheric background.

Place, publisher, year, edition, pages
2016. Vol. 824, no 2, L28
Keyword [en]
astroparticle physics, neutrinos
National Category
Astronomy, Astrophysics and Cosmology
Identifiers
URN: urn:nbn:se:uu:diva-299728DOI: 10.3847/2041-8205/824/2/L28ISI: 000378168200012OAI: oai:DiVA.org:uu-299728DiVA: diva2:949993
Funder
Swedish Research CouncilSwedish Polar Research SecretariatSwedish National Infrastructure for Computing (SNIC)Knut and Alice Wallenberg FoundationGerman Research Foundation (DFG)
Available from: 2016-07-26 Created: 2016-07-26 Last updated: 2016-07-26Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text

Search in DiVA

By author/editor
Boersma, David J.Botner, OlgaBurgman, AlexanderHallgren, AllanStröm, RickardUnger, Lisa
By organisation
Medical Radiation ScienceHigh Energy Physics
In the same journal
Astrophysical Journal Letters
Astronomy, Astrophysics and Cosmology

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 107 hits
ReferencesLink to record
Permanent link

Direct link