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Dissertation/Thesis Abstract

Spectral-Timing Analysis of Kilohertz Quasi-Periodic Oscillations in Neutron Star Low Mass X-Ray Binaries
by Troyer, Jon S., Ph.D., Wayne State University, 2018, 116; 10747548
Abstract (Summary)

Kilohertz quasi-periodic oscillations or kHz QPOs are X-ray intensity variations observed in neutron star low-mass X-ray binary (LMXB) systems. In such systems, matter is transferred from a secondary low-mass star to a neutron star via the process of accretion. kHz QPOs occur on the timescale of the inner accretion flow and may carry signatures of the physics of strong gravity (c2 ~ GM/R) and possibly clues to constraining the neutron star equation of state (EOS). No model to date has been able to illuminate the origin of kHz QPOs. Spectral-timing is a set of analysis techniques useful in deriving information about the nature of physical processes occurring within the accretion flow on the timescale of the kHz QPO. We present a comprehensive study of spectral-timing products of kHz QPOs from systems where data is available in NASA’s Rossi X-ray Timing Explorer (RXTE) archive to demonstrate the promise of these techniques and to gain insights regarding the origin of kHz QPOs. Using data averaged over the entire RXTE archive, we show correlated time-lags as a function of QPO frequency and energy, as well as energy-dependent covariance spectra for the various LMXB systems where spectral-timing analysis is possible. The similarity in trends in all sources suggest a common physical origin for kHz QPOs across the population. The diferences in results between lower and upper kHz QPOs lend further support to the evidence of the differing nature of the lower and upper kHz QPOs.

Indexing (document details)
Advisor: Cackett, Edward
Commitee: Cinabro, David, Miller, Jon, Pruneau, Claude
School: Wayne State University
Department: Physics
School Location: United States -- Michigan
Source: DAI-B 79/08(E), Dissertation Abstracts International
Subjects: Astrophysics, Physics
Keywords: Kilohertz quasi–periodic oscillations, Neutron star low mass X-ray binaries, Spectral–timing analysis
Publication Number: 10747548
ISBN: 978-0-355-82721-7
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