Multidimensional Late-Time Modeling of Type Ia Supernova Spectra

Type Ia supernovae (SNe Ia) have been used successfully to derive constraints on the expansion history of our universe. They are also a source of kinetic energy and iron-group elements in galaxies, and they are inherently interesting cosmic events whose study requires the application of sophisticated algorithms and computational architectures. Late-time, or nebular, observations of SNe Ia are taken during the phase in which the ejecta are optically thin and are heated by radioactive decay of iron-group elements. They are a powerful and unique probe of ejecta properties and may be used to infer information about the explosion itself. In this thesis, I present a three-dimensional radiative transfer code to calculate the properties and synthetic data of optically thin, homologously-expanding gases illuminated by radioactive decay energy and apply it to a variety of SN Ia explosion models. I derive the relationship between key explosion properties and nebular spectra using a suite of parametrized models, which results in the identification of a number of degeneracies. I also present the first-ever multidimensional nebular spectra of SNe Ia interacting with a binary companion, which leads us to rule out classic single-degenerate systems as SN Ia progenitors

Discovery of Selective Small Molecule Type III Phosphatidylinositol 4‑Kinase Alpha (PI4KIIIα) Inhibitors as Anti Hepatitis C (HCV) Agents

Hepatitis C virus (HCV) assembles many host cellular proteins into unique membranous replication structures as a prerequisite for viral replication, and PI4KIIIα is an essential component of these replication organelles. RNA interference of PI4KIIIα results in a breakdown of this replication complex and cessation of HCV replication in Huh-7 cells. PI4KIIIα is a lipid kinase that interacts with the HCV nonstructural 5A protein (NS5A) and enriches the HCV replication complex with its product, phosphoinositol 4-phosphate (PI4P). Elevated levels of PI4P at the endoplasmic reticulum have been linked to HCV infection in the liver of HCV infected patients. We investigated if small molecule inhibitors of PI4KIIIα could inhibit HCV replication in vitro. The synthesis and structure–activity relationships associated with the biological inhibition of PI4KIIIα and HCV replication are described. These efforts led directly to identification of quinazolinone <b>28</b> that displays high selectivity for PI4KIIIα and potently inhibits HCV replication in vitro

Broad-Line Reverberation In The Kepler-Field Seyfert Galaxy Zw 229-015

The Seyfert 1 galaxy Zw 229-015 is among the brightest active galaxies being monitored by the Kepler mission. In order to determine the black hole mass in Zw 229-015 from H beta reverberation mapping, we have carried out nightly observations with the Kast Spectrograph at the Lick 3 m telescope during the dark runs from 2010 June through December, obtaining 54 spectroscopic observations in total. We have also obtained nightly V-band imaging with the Katzman Automatic Imaging Telescope at Lick Observatory and with the 0.9 m telescope at the Brigham Young University West Mountain Observatory over the same period. We detect strong variability in the source, which exhibited more than a factor of two change in broad H beta flux. From cross-correlation measurements, we find that the H beta light curve has a rest-frame lag of 3.86(-0.90)(+0.69) days with respect to the V-band continuum variations. We also measure reverberation lags for H alpha and H gamma and find an upper limit to the H delta lag. Combining the H beta lag measurement with a broad H beta width of sigma(line) = 1590 +/- 47 km s(-1) measured from the rms variability spectrum, we obtain a virial estimate of M-BH = 1.00(-0.24)(+0.19) x 10(7) M-circle dot for the black hole in Zw 229-015. As a Kepler target, Zw 229-015 will eventually have one of the highest-quality optical light curves ever measured for any active galaxy, and the black hole mass determined from reverberation mapping will serve as a benchmark for testing relationships between black hole mass and continuum variability characteristics in active galactic nuclei.NSF AST-0548198, AST-0908886, AST-0618209, NSF-0642621TABASGO FoundationGary and Cynthia BengierRichard and Rhoda Goldman FundSun Microsystems, Inc.Hewlett-Packard CompanyAuto-Scope CorporationLick ObservatoryUniversity of CaliforniaSylvia & Jim Katzman FoundationPackard FellowshipMinistry of Education, Science and Technology 2010-0021558NASAMarc J. Staley for a Graduate FellowshipAstronom