The Extremes of Neutrino Astronomy : From Fermi Bubbles with IceCube to Ice Studies with ARIANNA
The Fermi bubbles are extended regions of hard gamma-ray emission which were discovered with Fermi-LAT data to exist above and below the Galactic Center. In order to explain the origin of the gamma-rays, different theories are proposed. In particular, within hadronic models, highly-accelerated cosmi...
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ftuppsalauniv:oai:DiVA.org:uu-383629 2023-05-15T14:08:45+02:00 The Extremes of Neutrino Astronomy : From Fermi Bubbles with IceCube to Ice Studies with ARIANNA Unger, Elisabeth 2019 application/pdf http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-383629 eng eng Uppsala universitet, Högenergifysik Uppsala Uppsala Dissertations from the Faculty of Science and Technology, 1104-2516 137 http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-383629 urn:isbn:978-91-513-0682-7 info:eu-repo/semantics/openAccess astroparticle physics neutrino telescopes IceCube Fermi bubbles ARIANNA horizontal propagation surface wave propagation Subatomic Physics Subatomär fysik Astronomy Astrophysics and Cosmology Astronomi astrofysik och kosmologi Doctoral thesis, monograph info:eu-repo/semantics/doctoralThesis text 2019 ftuppsalauniv 2023-03-15T23:29:43Z The Fermi bubbles are extended regions of hard gamma-ray emission which were discovered with Fermi-LAT data to exist above and below the Galactic Center. In order to explain the origin of the gamma-rays, different theories are proposed. In particular, within hadronic models, highly-accelerated cosmic rays interact with interstellar matter and create the observed gamma-rays and in addition neutrinos. Data from the neutrino detector IceCube was analyzed using a maximum likelihood method. An upper limit on the possible neutrino flux from the Fermi bubbles at energies between 10 GeV and 200 GeV was determined. While this analysis is performed with the lowest energies IceCube can reach, the ARIANNA (Antarctic Ross Ice-shelf ANtenna Neutrino Array) experiment has the goal to detect the highest energy neutrinos by measuring radio wave radiation produced by their interaction products in the ice. With ARIANNA the propagation of radio waves in the firn (packed snow) of the Ross Ice Shelf was investigated. According to the classical approach the radio waves, produced in the firn, are supposed to bend down because of the changing density, and therefore changing refractive index, an effect which is called “shadowing”. Evidence that the waves can travel horizontally over a long distance will be presented. The horizontally propagating signals between two boreholes and to the ARIANNA stations were analyzed and characterized. Analyses were performed under two hypotheses to determine attenuation lengths for horizontal propagation signals. The results showed attenuation lengths between 310 m ± 83 m and 651 m ± 270 m, depending on the assumed hypothesis and performed analysis. In addition unexpected signals consistent with radio waves propagating along the firn surface, here called pre-pulses, were observed and characterized. Doctoral or Postdoctoral Thesis Antarc* Antarctic Ice Shelf Ross Ice Shelf Uppsala University: Publications (DiVA) Antarctic Ross Ice Shelf |
institution |
Open Polar |
collection |
Uppsala University: Publications (DiVA) |
op_collection_id |
ftuppsalauniv |
language |
English |
topic |
astroparticle physics neutrino telescopes IceCube Fermi bubbles ARIANNA horizontal propagation surface wave propagation Subatomic Physics Subatomär fysik Astronomy Astrophysics and Cosmology Astronomi astrofysik och kosmologi |
spellingShingle |
astroparticle physics neutrino telescopes IceCube Fermi bubbles ARIANNA horizontal propagation surface wave propagation Subatomic Physics Subatomär fysik Astronomy Astrophysics and Cosmology Astronomi astrofysik och kosmologi Unger, Elisabeth The Extremes of Neutrino Astronomy : From Fermi Bubbles with IceCube to Ice Studies with ARIANNA |
topic_facet |
astroparticle physics neutrino telescopes IceCube Fermi bubbles ARIANNA horizontal propagation surface wave propagation Subatomic Physics Subatomär fysik Astronomy Astrophysics and Cosmology Astronomi astrofysik och kosmologi |
description |
The Fermi bubbles are extended regions of hard gamma-ray emission which were discovered with Fermi-LAT data to exist above and below the Galactic Center. In order to explain the origin of the gamma-rays, different theories are proposed. In particular, within hadronic models, highly-accelerated cosmic rays interact with interstellar matter and create the observed gamma-rays and in addition neutrinos. Data from the neutrino detector IceCube was analyzed using a maximum likelihood method. An upper limit on the possible neutrino flux from the Fermi bubbles at energies between 10 GeV and 200 GeV was determined. While this analysis is performed with the lowest energies IceCube can reach, the ARIANNA (Antarctic Ross Ice-shelf ANtenna Neutrino Array) experiment has the goal to detect the highest energy neutrinos by measuring radio wave radiation produced by their interaction products in the ice. With ARIANNA the propagation of radio waves in the firn (packed snow) of the Ross Ice Shelf was investigated. According to the classical approach the radio waves, produced in the firn, are supposed to bend down because of the changing density, and therefore changing refractive index, an effect which is called “shadowing”. Evidence that the waves can travel horizontally over a long distance will be presented. The horizontally propagating signals between two boreholes and to the ARIANNA stations were analyzed and characterized. Analyses were performed under two hypotheses to determine attenuation lengths for horizontal propagation signals. The results showed attenuation lengths between 310 m ± 83 m and 651 m ± 270 m, depending on the assumed hypothesis and performed analysis. In addition unexpected signals consistent with radio waves propagating along the firn surface, here called pre-pulses, were observed and characterized. |
format |
Doctoral or Postdoctoral Thesis |
author |
Unger, Elisabeth |
author_facet |
Unger, Elisabeth |
author_sort |
Unger, Elisabeth |
title |
The Extremes of Neutrino Astronomy : From Fermi Bubbles with IceCube to Ice Studies with ARIANNA |
title_short |
The Extremes of Neutrino Astronomy : From Fermi Bubbles with IceCube to Ice Studies with ARIANNA |
title_full |
The Extremes of Neutrino Astronomy : From Fermi Bubbles with IceCube to Ice Studies with ARIANNA |
title_fullStr |
The Extremes of Neutrino Astronomy : From Fermi Bubbles with IceCube to Ice Studies with ARIANNA |
title_full_unstemmed |
The Extremes of Neutrino Astronomy : From Fermi Bubbles with IceCube to Ice Studies with ARIANNA |
title_sort |
extremes of neutrino astronomy : from fermi bubbles with icecube to ice studies with arianna |
publisher |
Uppsala universitet, Högenergifysik |
publishDate |
2019 |
url |
http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-383629 |
geographic |
Antarctic Ross Ice Shelf |
geographic_facet |
Antarctic Ross Ice Shelf |
genre |
Antarc* Antarctic Ice Shelf Ross Ice Shelf |
genre_facet |
Antarc* Antarctic Ice Shelf Ross Ice Shelf |
op_relation |
Uppsala Dissertations from the Faculty of Science and Technology, 1104-2516 137 http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-383629 urn:isbn:978-91-513-0682-7 |
op_rights |
info:eu-repo/semantics/openAccess |
_version_ |
1766280784200597504 |