Gravitational waves and short gamma ray bursts

Predoi, Valeriu ORCID: https://orcid.org/0000-0002-9729-6578 2012. Gravitational waves and short gamma ray bursts. PhD Thesis, Cardiff University. Item availability restricted.

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Abstract

Short hard gamma-ray bursts (GRB) are believed to be produced by compact binary coalescences (CBC) { either double neutron stars or neutron star{black hole binaries. The same source is expected to emit strong gravitational radiation, detectable with existing and planned gravitational wave observatories. The focus of this work is to describe a series of searches for gravitational waves (GW) from compact binary coalescence (CBC) events triggered by short gamma-ray burst detections. Specifically, we will present the motivation, frameworks, implementations and results of searches for GW associated with short gamma-ray bursts detected by Swift, Fermi{GBM and the InterPlanetary Network (IPN) gamma-ray detectors. We will begin by presenting the main concepts that lay the foundation of gravitational waves emission, as they are formulated in the theory of General Relativity; we will also brie y describe the operational principles of GW detectors, together with explaining the main challenges that the GW detection process is faced with. Further, we will motivate the use of observations in the electromagnetic (EM) band as triggers for GW searches, with an emphasis on possible EM signals from CBC events. We will briefly present the data analysis techniques including concepts as matched{filtering through a collection of theoretical GW waveforms, signal{to{ noise ratio, coincident and coherent analysis approaches, signal{based veto tests and detection candidates' ranking. We will use two different GW{GRB search examples to illustrate the use of the existing coincident and coherent analysis methods. We will also present a series of techniques meant to improve the sensitivity of existing GW triggered searches. These include shifting background data in time in order to obtain extended coincident data and setting a prior on the GRB inclination angle, in accordance with astrophysical observations, in order to restrict the searched parameter space. We will describe the GW data analysis and present results from a GW search around 12 short gamma-ray bursts detected by the InterPlanetary Network (IPN) between 2006 and 2007. The IPN{detected bursts usually have extended localization error boxes and a search for GW was performed at different sky locations across these error regions. Since no GW detection was made, we set upper limits on the distances to the GRB progenitors; we briefly discuss the implications that two IPN GRBs error regions overlap two nearby galaxies.

Item Type:	Thesis (PhD)
Status:	Unpublished
Schools:	Physics and Astronomy
Subjects:	Q Science > QB Astronomy
Uncontrolled Keywords:	gravitational waves ; data analysis ; short gamma-ray bursts ; radio transients ; InterPlanetary Network ; LIGO ; Virgo laser interferometers
Funders:	STFC
Date of First Compliant Deposit:	30 March 2016
Last Modified:	21 Oct 2022 10:22
URI:	https://orca.cardiff.ac.uk/id/eprint/39987

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