Date of Degree
PhD (Doctor of Philosophy)
First Committee Member
Gayley, Kenneth G.
Second Committee Member
Hill, Joanne E.
Third Committee Member
Lang, Cornelia C.
Fourth Committee Member
Kletzing, Craig A.
Ultraluminous X-ray (ULX) sources are non-nuclear extragalactic accreting compact objects whose X-ray luminosities exceed the Eddington limit for stellar mass black hole binaries (BHB). Their high luminosities suggest they are either intermediate mass black holes, that their emission is beamed, or that they are emitting at super-Eddington rates. We observed the ULX IC 342 X-1 simultaneously in X-ray and radio with Chandra and the VLA to investigate previously reported unresolved radio emission coincident with the ULX. The Chandra spectrum appears to be consistent with an accretion disc-dominated thermal state and suggests a mass of the black hole using the modeled inner disc temperature to be 157Mʘ ≤ M √ (cosi) ≤ 200 Mʘ. No significant radio emission was observed, consistent with the source being in a thermal disc-dominated state. Reanalysis of previous X-ray observations of the source shows that high energy curvature often interpreted as evidence for supercritical accretion cannot confidently be identified using the 2-10 keV energy band.
Black hole systems such as BHBs, ULXs, and AGN represent the greatest test labs in the universe for the study of extreme gravity. Emission from the accretion disk and scattering from the surrounding corona allow study of the ultra-strong gravity and magnetic fields very near the central BH engine. However, many of these effects are imprinted as polarization of the emission and are invisible to spectral and timing studies alone. The outflows from AGN are also thought to play a key role in galaxy shaping and cluster formation. High efficiency and spectral resolution are required to measure ionization-velocities and density parameters from these sources to constrain the outflow structure. Beamline studies and theoretical modeling were carried out to characterize the throughput and spectral resolving power of off-plane gratings for use in future x-ray observatories which will make these measurements. Additionally, synchrotron measurements were carried out to test theoretical predictions of strong polarization response for off-plane diffraction gratings. The empirical results of this study are the first to demonstrate a lack of polarization sensitivity for grazing-incidence off-plane gratings and support more complex modeling results than used previously.
X-ray astronomy gives observers a window into extreme environments such as black hole binary systems (BHBs), Gamma-ray bursts (GRBs), and active galactic nuclei (AGN). Because X-rays do not penetrate Earth's atmosphere, X-ray observatories must be built to survive launch and operate on sounding rocket, space station, and satellite platforms. This thesis work focuses on the study of X-ray emitting sources and the development of next generation X-ray instrumentation, specifically off-plane diffraction gratings, which will yield the clearest picture yet of the these X-ray sources and how they shape the universe around them.
publicabstract, Black Holes, Diffraction, Gamma-ray Bursts, Gratings, Polarimetry, X-ray
xiv, 96 pages
Includes bibliographical references (pages 87-96).
Copyright 2016 Hannah Rebecca Marlowe
Marlowe, Hannah Rebecca. "Polarimetric and spectrographic instrumentation to enable next generation x-ray observatories." PhD (Doctor of Philosophy) thesis, University of Iowa, 2016.