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A New Sensor for Milky-Way Particle Accelerators: The Standalone-Radio Cosmic Ray Detector at the Owens Valley Radio Observatory Long Wavelength Array


Plant, Kathryn Annette (2024) A New Sensor for Milky-Way Particle Accelerators: The Standalone-Radio Cosmic Ray Detector at the Owens Valley Radio Observatory Long Wavelength Array. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/vgew-6g30.


This thesis describes the development of a standalone radio cosmic ray detector at the Owens Valley Radio Observatory Long Wavelength Array (OVRO-LWA), for the purpose of understanding the high-energy limits of Milky Way particle accelerators. A shift from Milky Way cosmic ray sources to extragalactic accelerators likely occurs for particle energies somewhere between 1--1000 PeV. Placing the shift at the lower end of this range creates challenges explaining certain features of the cosmic ray spectrum at high energies, but placing the shift at the high-energy end of the range requires unknown types of Milky Way cosmic ray sources.

I have built a cosmic ray detection system as part of a major upgrade to the OVRO-LWA. The OVRO-LWA array layout and the fast digital signal processing hardware led to the cosmic ray search strategy chosen here. A key part of this thesis work was developing a process for rejecting radio frequency interference as well as developing a system to search for cosmic rays among subsets of antennas but save snapshots of data from all 352 dual-polarization LWA antennas at once. In this thesis, the presentation of the OVRO-LWA cosmic ray detector is bracketed by an exploration of the landscape of Milky Way cosmic rays, beginning with an overview chapter and finishing with an investigation of a specific habitat for relativistic particles: the large-scale magnetosphere of a flare star at the end of the main sequence.

Since cosmic ray trajectories do not point back to their sources, identifying their origins will require precise measurement of shifts in cosmic ray mass composition---a measurement which this thesis has set the OVRO-LWA on the path toward making.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:cosmic rays, digital signal processing, radio astronomy
Degree Grantor:California Institute of Technology
Division:Physics, Mathematics and Astronomy
Major Option:Astrophysics
Awards:Everhart Lecture, August 2023.
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Hallinan, Gregg W. (advisor)
  • Romero-Wolf, Andrew (co-advisor)
Thesis Committee:
  • Kulkarni, Shrinivas R. (chair)
  • Ravi, Vikram
  • Bouman, Katherine L.
  • Phinney, E. Sterl
  • Hallinan, Gregg W.
  • Romero-Wolf, Andrew
Defense Date:15 August 2023
Funding AgencyGrant Number
NSF Graduate Research FellowshipUNSPECIFIED
Record Number:CaltechTHESIS:08262023-021312243
Persistent URL:
Related URLs:
URLURL TypeDescription work: "A continuously-operating standalone radio cosmic ray detection system at the OVRO-LWA" work" "Updates from the OVRO-LWA: Commissioning a Full-Duty-Cycle Radio-Only Cosmic Ray Detector"
Plant, Kathryn Annette0000-0001-6360-6972
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:16166
Deposited By: Kathryn Plant
Deposited On:11 Sep 2023 15:11
Last Modified:29 May 2024 19:39

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