Thesis
HaloSat observations of the Cygnus Loop
University of Iowa
Master of Science (MS), University of Iowa
Summer 2021
DOI: 10.17077/etd.005921
Abstract
HaloSat was a type of small satellite known as a CubeSat that used 3 co-aligned silicondrift detectors to make x-ray emission measurements in the 0.4-7 keV energy range from astrophysical sources.
The Cygnus Loop is a supernova remnant 735 parsecs from Earth, making it one of the closest SNRs. It is approximately 3 ◦ in diameter and is a strong source of soft x-rays. HaloSat provided the first full view in x-rays of the Cygnus Loop with moderate energy resolution. It was determined to have 2 dominant plasma temperatures: kT ≈0.17 keV in collisional ionization equilibrium, and kT ≈0.58 keV in non-equilibrium. Sub-solar oxygen abundances were found, 0.17 and 0.60 solar for low and high temperatures respectively. HaloSat’s large field of view enabled measurement of the total energy flux as ≈1.9×10^−8 ergs cm −2 s −1 in the 0.4-7 keV energy band. The total luminosity for the Cygnus Loop in the same energy
band was determined to be 1.2 × 10^36 ergs s −1 .
The brightness of the Cygnus Loop in soft x-rays makes it an ideal target for calibrating HaloSat’s detectors. HaloSat gathered data over several observations each spread out over the course of its 2-year operating time, allowing for a time-evolution analysis to be performed on HaloSat’s 3 detectors. No significant change in sensitivity occurred over time. However, one detector was found to be more sensitive in the lower energies (0.5-0.7 keV) compared to the other two, and the response calculation should be modified accordingly.
Details
- Title: Subtitle
- HaloSat observations of the Cygnus Loop
- Creators
- Jacob Richardson
- Contributors
- Philip Kaaret (Advisor)Steven Spangler (Committee Member)Casey DeRoo (Committee Member)
- Resource Type
- Thesis
- Degree Awarded
- Master of Science (MS), University of Iowa
- Degree in
- Astronomy
- Date degree season
- Summer 2021
- DOI
- 10.17077/etd.005921
- Publisher
- University of Iowa
- Number of pages
- xii, 51 pages
- Copyright
- Copyright 2021 Jacob Richardson
- Language
- English
- Description illustrations
- color illustrations
- Description bibliographic
- Includes bibliographical references (pages 46-510
- Public Abstract (ETD)
HaloSat was a type of small satellite known as a CubeSat that was about the size a shoe box and orbited around the Earth from 13 July 2018 to 4 January 2020. While in orbit, it measured x-rays from astrophysical objects to enable us to understand their physical properties. One such object is the Cygnus Loop.
The Cygnus Loop is a supernova remnant, which is the remains of an exploded star. The explosion (called a supernova) is one of the most energetic events known in the universe and heats material around it so hot (millions of degrees Kelvin) that it can produce x-rays. The Cygnus Loop strongly produces x-rays that HaloSat can detect making it an ideal source for calibrating the instruments HaloSat uses to detect the x-rays.
Using HaloSat, we took the first full-view observations of the Cygnus Loop with moderate spectral resolution. I measured physical properties of the Cygnus Loop including temperature and energy output in the x-ray band. Because the observations were spread out over 2 years, an inspection of how HaloSat’s detectors’ sensitivity to x-rays changed over time was possible and was determined to be negligible.
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984124761902771
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