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Thesis - Stoch GW and LIGOv9-Final.pdf (2.11 MB)

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Fact Checking LIGO's Radiometer Code with Simulated LIGO Data

Thrush, Samantha Elaine
http://rave.ohiolink.edu/etdc/view?acc_num=ouhonors1428923532

Abstract Details

2015, Bachelor of Science (BS), Ohio University, Astrophysics.
Gravitational waves are predicted by general relativity to be emitted from very massive and fast-moving objects, ranging from cosmological sources to astrophysical objects. Two examples of such objects that pertain to this project are a neutron star in a binary system, such as Scorpius X-1, or black holes in a binary system. A key set of instruments that are used to search for gravitational waves are the LIGO detectors, which utilize interferometry in order to observe gravitational wave signals. As the signal strength is expected to be small relative to the background noise from a single LIGO detector, data from two detectors are cross-correlated to increase sensitivity to any potential gravitational waves. In order to test the effectiveness of the cross-correlation 'radiometer' code in detecting point sources similar to Scorpius X-1 near frequency bin borders, the code was modified to have the capability to add multiple simulated pulsar signals. To check that the changes to the radiometer code did not adversely affect the results reached by the code, two trials were run. The first trial, the Troubleshooting Trial, read in real LIGO data through the traditional means and explored the effects of adding simulated data via the modified code. The graphs from this trial were then graded on three criteria to ascertain if the modified code worked as expected and did not introduce error. Once the modified code completed its vetting, a second trial, the Bin Shifting Trial, was used to ascertain how well injected signals can be recovered when they fall on the border between frequency bins. Through a series of seven tests, simulated signals were created with peak frequencies ranging from being on a bin border to half a bin border away, where the bin sizing was 0.25 Hz. Uniform attenuation was expected on the trial with frequencies on the bin border, and the trial with the signals located between two bin borders was expected to have the smallest attenuation. These tests revealed anomalous attenuation for three of the signals in all cases in the bin shift trial, with normal attenuation occurring in the rest of the simulated signals. Two of these anomalously attenuated signals seemed to be created by a peak masking routine found in stochastic.m, while the other anomalous peaks are currently unaccounted for. In addition, both trials experienced abnormal attenuation at times, which needs to be further investigated. In order to have a greater understanding of the data’s behavior, there needs to be further exploration of the codes at hand with more thorough testing with smaller frequency shifting of signals, as well as additional tests that test more signal frequencies around the strangely attenuated signals.
Douglas Clowe (Advisor)
66 p.
Astronomy; Astrophysics; Physics
LIGO; radiometer code; stochastic; gravitational waves

Recommended Citations

Citations

  • Thrush, S. E. (2015). Fact Checking LIGO's Radiometer Code with Simulated LIGO Data [Undergraduate thesis, Ohio University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ouhonors1428923532

    APA Style (7th edition)

  • Thrush, Samantha. Fact Checking LIGO's Radiometer Code with Simulated LIGO Data. 2015. Ohio University, Undergraduate thesis. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ouhonors1428923532.

    MLA Style (8th edition)

  • Thrush, Samantha. "Fact Checking LIGO's Radiometer Code with Simulated LIGO Data." Undergraduate thesis, Ohio University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=ouhonors1428923532

    Chicago Manual of Style (17th edition)

ouhonors1428923532
445
© 2015, all rights reserved.
This open access ETD is published by Ohio University Honors Tutorial College and OhioLINK.