Astrophysics and Astronomy Commons^™

Reflection And Reverberation In Neutron Star Low-Mass X-Ray Binaries, Benjamin Coughenour

Wayne State University Dissertations

Neutron star low-mass X-ray binaries (NS LMXBs) are systems which consist of a NS and a low-mass companion star. They are naturally variable on a variety of timescales, and are even classified by their X-ray spectral variability on the timescales of hours to days. The most luminous NS LMXB sources are known as ‘Z’ sources, because they trace out a characteristic ‘Z’ shape when plotted on a color-color or hardness-intensity diagram. The physical mechanisms causing this variability are not well understood. To try to address this, we model spectra taken from different positions on a hardness-intensity diagram of two Z …

Spectral–Timing Analysis Of Kilohertz Quasi–Periodic Oscillations In Neutron Star Low Mass X-Ray Binaries, Jon Troyer

Wayne State University Dissertations

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 …

Crustal Cooling In The Neutron Star Low-Mass X-Ray Binary Ks 1731−260, Rachael Lynn Merritt

Wayne State University Theses

Neutron stars in binary systems can undergo periods of accretion (outburst), where in- falling material heats the crust of the star out of thermal equilibrium with the core. When accretion stops (quiescence), we can directly observe the thermal relaxation of the crust. Crustal cooling of accretion-heated neutron stars provides insight into the stellar interior of neutron stars. The neutron star X-ray transient, KS 1731−260, was in outburst for 12.5 years before returning to quiescence in 2001. Here, we present a 150 ks Chandra observation of KS 1731−260 taken in August 2015, about 14.5 years into quiescence. We find that the …

Molecular Regulation Of Trophoblast Survival During Placentation And Pathologies Of Placental Insufficiency, Chandni V. Jain

Wayne State University Dissertations

HBEGF, is present in the uterus at the time of embryo implantation and protects first

trimester TB cells from apoptosis and promotes their invasion. The hypertensive disease, PE, in

which TB invasion of the uterine arteries is reduced and TB apoptosis is elevated, is

characterized by a reduction in HBEGF expression. In this study using a first trimester cell line

and villous explant culture key components involved in HBEGF survival signaling pathway were

identified. Specific MMP inhibitors established the requirement for MMP2 in HBEGF shedding

and upregulation. NGS identified a HIF regulated gene, HSPA6 (HSP70B’) and using specific

inhibitors it …

An Automated System To Measure The Quantum Efficiency Of Ccds For Astronomy, Rebecca Ann Coles

Wayne State University Dissertations

We describe a system to measure the Quantum Efficiency in the wavelength range of 300nm to 1100nm of 40x40 mm n-channel CCD sensors for the construction of the 3.2 gigapixel LSST focal plane. The technique uses a series of instruments to create a very uniform flux of photons of controllable intensity in the wavelength range of interest across the face the sensor. This allows the absolute Quantum Efficiency to be measured with an accuracy in the 1% range. This system will be part of a production facility at Brookhaven National Lab for the basic component of the LSST camera.

The Venus "Shell-Over-Star" Hieroglyph And Maya Warfare: An Examination Of The Interpretation Of A Mayan Symbol, Claudia Ann Voit

Wayne State University Theses

For decades, Maya scholars have associated the Mayan ―Shell-Star‖ (also referred to as ―Star-War‖) hieroglyph with Maya warfare. Put forward by scholars such as Floyd Lounsbury and David Kelley, and later advanced by Linda Schele, David Freidel, Ian Graham, Peter Matthews, Anthony Aveni and others, there are now dozens of published articles and chapters relating the hieroglyph to Venus and warfare. Venus is one of the most notable celestial objects outside of the Sun and Moon and was highly visible to the inhabitants of the Maya world. The Dresden Codex (an astronomical almanac) contains important information about the planet Venus, …

Oscillator Strength Measurements In Singly-Ionized, Doubly-Ionized And Neutral Lanthanides And Transition Elements (Sm, Nd, Pr, Gd, Cu, And Fe) Using Laser-Induced Breakdown Spectroscopy., Caleb Ryder

Wayne State University Dissertations

Models for stellar nucleosynthesis, age determinations for stars in the Milky Way's galactic halo, and stellar chemical abundance determinations are dependent upon accurate atomic spectroscopic data to allow the correct interpretation of stellar absorption and emission spectra. It is well known that calculations of many astrophysically important atomic parameters are limited due to line blending, insufficient spectral resolution of some key spectral lines, and also the complicated electronic structure of the important heavy elements. Astrophysicists have therefore looked to laboratory astrophysics experiments to provide accurate atomic data to help resolve these limiting issues. In this dissertation, laser-induced breakdown spectroscopy (LIBS) …

The Core Collapse Supernova Rate In The Sdss-Ii Supernova Survey, Matthew Frederick Taylor

Wayne State University Dissertations

The Sloan Digital Sky Survey II Supernova Survey (SDSS-II SN), though designed as a type Ia supernova search for cosmology, also discovered a large sample of core collapse supernovae (CCSN). I use the SDSS-II SN data to measure the volumetric CCSN rate in the redshift range (0.03 < z < 0.09), finding a volume-averaged rate of 0.98±0.18 ×10⊃−4⊃h⊂70⊂⊃3⊃yr⊃−1⊃Mpc⊃−3⊃. The CCSN luminosity function is also extracted from the data, and its implications on the cosmic star formation history are considered.