Browsing by Author "Penev, Kaloyan"
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Item An Eccentric Massive Jupiter Orbiting a Subgiant on a 9.5-day Period Discovered in the Transiting Exoplanet Survey Satellite Full Frame Images(Institute of Physics Publishing, 2019-05) Rodriguez, J. E.; Quinn, S. N.; Huang, C. X.; Vanderburg, A.; Penev, Kaloyan; Brahm, R.; Jordán, A.; 0000-0003-4464-1371 (Penev, K); Penev, KaloyanWe report the discovery of TOI-172 b from the Transiting Exoplanet Survey Satellite (TESS) mission, a massive hot Jupiter transiting a slightly evolved G star with a 9.48-day orbital period. This is the first planet to be confirmed from analysis of only the TESS full frame images, because the host star was not chosen as a two-minute cadence target. From a global analysis of the TESS photometry and follow-up observations carried out by the TESS Follow-up Observing Program Working Group, TOI-172 (TIC 29857954) is a slightly evolved star with an effective temperature of T_{eff} = 5645 ± 50 K, a mass of M_{∗} = 1.128_{-0.061} ^{+0.065} M ⊙, radius of R_{∗} = 1.777_{-0.044} ^{+0.047} R ⊙, a surface gravity of log g_{∗} = 3.993 _{-0.028} ^{+0.027}, and an age of 7.4 _{-1.5} ^{+1.6}. Its planetary companion (TOI-172 b) has a radius of R _{P} = 0.965 _{-0.029} ^{+0.032} R_{J}, a mass of M _{P} = 5.42 _{-0.20} ^{+0.22} M _{J}, and is on an eccentric orbit (e = 0.3806 _{-0.0090} ^{+0.0093} ). TOI-172 b is one of the few known massive giant planets on a highly eccentric short-period orbit. Future study of the atmosphere of this planet and its system architecture offer opportunities to understand the formation and evolution of similar systems. © 2019. The American Astronomical Society. All rights reserved..Item Analyzing Tidal Circularization In Exoplanet Systems To Determine The Tidal Dissipation Efficiency Of Giant Planets(August 2023) Mahmud, Mohammad M 1986-; Penev, Kaloyan; Wu, Yunan; King, Lindsay J.; Kesden, Michael; Ishak-Boushaki, Mustapha; Anderson, PhillipA planet in the gravitational field of its parent star experiences a tidal force due to the variation of the gravitation at different points on it at different distances from the star. The planet gets distorted, being stretched by this difference of gravity. This distortion raises two bulges (called “tidal bulges”) along the star-planet joining line on two opposite sides of the planet (p). When it (p) revolves in an eccentric orbit, the tidal distortion varies since the tidal force varies with the distance from the star. The repetitive tidal distortion causes a periodic variation of the amplitude of the tidal bulges. The difference between the planet’s rotational angular speed and the system’s orbital angular speed also varies with the planet-star distance. It causes the tidal bulges to move around the planet, creating a tidal wave. The friction and viscous force within the different layers of the planet resist the motion of the tidal wave and the variation of its amplitude, resulting in the generation of heat. Ultimately, some portion of the system’s orbital energy converts into heat. The gradual loss of the system’s orbital energy reduces the orbital eccentricity and semimajor axis. A ubiquitously used term that parameterizes tidal dissipation is the modified tidal quality factor (Q′ pl). Q′ pl is inversely proportional to the tidal dissipation rate. In this project, we determined a possible range of Q′ pl of short-period gas giants. The periodically varying tide acting on different parts of the planet, sometimes coupling with other forces (like Coriolis force), generates multiple components of the tidal wave that depend on the time-dependent tidal frequency. So we prescribe an empirical model where Q′ pl may depend on the frequency to consider different possible tidal wave components. We applied our analysis to 78 exoplanet systems consisting of a single planet orbiting a single host star. We worked out an allowed range of the frequency-dependent Q′ pl for each system and combined them to find general constraints on Q′ pl. We determined the upper limit of Q′ pl by requiring that if the system starts evolution with a sufficiently high initial eccentricity, then the eccentricity simulated at the present age for which the simulated orbital period matches the measured value of the orbital period, should be lower than the envelope observed in the ‘eccentricity vs. semimajor axis to planetary radius scatter plot’ of a collection of exoplanet systems. We determined the lower limit of the same parameter by requiring that it should not be lower than the measured orbital eccentricity at the present age. We find that the value of log10 Q′ pl for HJs is 5.0 ± 0.5 for the range of tidal period from 0.8 to 7 days. We do not see any clear sign of frequency dependence of Q′ pl within the mentioned uncertainties.Item Circularization of Tidal Disruption Streams for Schwarzschild Black Holes and Distribution of Orbital Inclinations of Tidally Disrupted Stars for Kerr Black Holes(2021-12-01T06:00:00.000Z) Rossi, Joseph D; Kesden, Michael; Akbar, Mohammed; Ishak-Boushaki, Mustapha; King, Lindsay; Penev, Kaloyan; Anderson, PhillipTidal Disruption Events (TDEs) occur when a star approaches sufficiently close to a supermassive black hole (SMBH) such that the tidal gravitational field of the SMBH overcomes the self-gravity of the star, causing the star to rip apart. A stream of debris is formed from the star’s remnants, which proceeds to orbit about the black hole. Relativistic apsidal precession causes leading elements of the stream to collide with trailing elements, dissipating energy on the way to circularization. We explore this circularization process for Schwarzschild, or spherically symmetric, SMBHs, finding that the process is likely to take longer than was first expected, and uncovering two distinct regimes of circularization. We then show work on how TDE rates depend on orbital inclination for Kerr, or axisymmetric SMBHs.Item Constraining Tidal Quality Factor in Low-mass Eclipsing Binaries Using Tidal Synchronization(2022-12-01T06:00:00.000Z) Patel, Ruskin 1992-; Penev, Kaloyan; Goux, Warren J.; Kesden, Michael; Ishak-Boushaki, Mustapha; King, Lindsay J.; Anderson, Phillip C.Tides play a crucial role in shaping the evolution of the bodies in binary systems. With the discovery of close-in hot Jupiter systems from exoplanet missions such as Kepler and TESS, it has become imperative to understand the tidal effects, which can shed light on their formation and observed orbital properties. Various models proposed in the literature come with some inherent assumptions on the evolution of binary systems under the influence of tides. The tidal dissipation in stars or planets is generally studied empirically using an efficiency parameter, commonly known as the Tidal Quality Factor (Q∗). Throughout the literature, significant inconsistencies exist in the constraints obtained on Q∗. In this thesis, we aim to remove these inconsistencies by relaxing some of the assumptions previously made and exploring the dependencies of Q∗ on stellar and orbital properties. We perform Monte Carlo Markov Chain simulations to find tight constraints on Q∗ using the observed rotation periods of primary star in eclipsing binary systems, selected from the Kepler Catalog.Item Design and Synthesis of Polymer Nanocomposites for Additive Manufacturing(May 2023) Perera, Sachini Dilinika 1992-; Penev, Kaloyan; Smaldone, Ronald A; Ferraris, John P.; Biewer, Michael C.; Gassensmith, Jeremiah J.Additive manufacturing or 3D printing is a process where the materials are deposited in a layer- by-layer fashion according to a pre-designed computer aided file to fabricate required geometries. There are a wide range of materials from thermoplastics, polymeric resins, metals, alloys, nanocomposites, to hydrogels that have been used in 3D printing, as well as several different types of processes are available for 3D printing. Fused filament fabrication, ink jet printing, stereolithography (SLA) and digital light projection (DLP) can be recognized as the most popular and affordable techniques. This manufacturing technique is very promising as a user friendly, customizable setup without the need to manufacture through expensive molding processes or producing waste from subtractive manufacturing methods such as milling. Even though it possesses all the advantages, poor interlayer adhesion, limited mechanical properties, low resolution and rough surface finish is limiting its applications at large scale. Vat photopolymerization 3D printing techniques provide better resolution as high as 10 μm for the printed parts from SLA and DLP compared to other 3D printing techniques. Here, a photo resin that contains photocurable monomers and oligomers, crosslinkers are polymerized in a print vat using UV irradiation in the presence of a photoinitiator. The photo printed structures show fine resolution and smooth surface finish, yet the mechanical properties of the printed parts are inadequate for end use applications. To address this limitation different approaches were taken and studied, thus the overall goal of this research was to enhance properties of 3D printed objects and to develop methodologies to improve photo printing processes that would ultimately improve intrinsic properties of the photo printed materials. Chapter 1 of the dissertation provides a literature review about 3D printing techniques, materials, and the limitations of additive manufacturing. This chapter further discusses the approaches taken to overcome the limitations by introducing ways to improve the mechanical properties. Chapter 2 describes our work in enhancing mechanical properties through a nanofiller derived from Kevlar and how we successfully 3D printed photoresin formulations using stereolithography without compromising printability. We discuss a methodology that can be used to incorporate unprocessable fibrous fillers in a resin formulation. Chapter 3 provides insights about how supramolecular interactions provide 3D printable materials with noncovalent cross-linking and stimuli-responsive properties to improve their processability and functionality. We evaluated urea formulations with aliphatic and aromatic sidechains and showed physical evidence for the presence of hydrogen bonding using variable temperature Fourier transform infrared (VT-ATR-FTIR) spectroscopy and van’t Hoff analysis. The self- healing efficiency of these formulations was characterized by measuring the recovery of their tensile mechanical properties. Chapter 4 describes our approach to process Metal Organic-Frameworks in vat photopolymerization. A new method is introduced to construct complex structures with fine features by integrating high loading weight percentages of MOF crystals to a photocurable acrylate formulation. Through free radical polymerization in a DLP setup, MOF loaded nanocomposites were 3D printed, and its catalytic performances were studied.Item HAT-TR-318-007: A Double-Lined M Dwarf Binary with Total Secondary Eclipses Discovered by HATNet and Observed by K2(Institute of Physics Publishing) Hartman, J. D.; Quinn, S. N.; Bakos, G. A.; Torres, G.; Kovács, G.; Latham, D. W.; Noyes, R. W.; Shporer, A.; Fulton, B. J.; Esquerdo, G. A.; Everett, M. E.; Penev, Kaloyan; Bhatti, W.; Csubry, Z.; 0000-0003-4464-1371 (Penev, K); Penev, KaloyanWe report the discovery by the HATNet survey of HAT-TR-318-007, a P = 3.34395390 ± 0.00000020 day period detached double-lined M dwarf binary with total secondary eclipses. We combine radial velocity (RV) measurements from TRES/FLWO 1.5 m and time-series photometry from HATNet, FLWO 1.2 m, BOS 0.8 m, and NASA K2 Campaign 5, to determine the masses and radii of the component stars: MA = 0.448 ± 0.011M⊙ N, MB 0.2721-0.0042 +0.0041 M⊙ N, RA 0.4548-0.0036 +0.0035R⊙ N, and RB 0.2913-0.0024 +0.0023R⊙ N. We obtained a FIRE/Magellan near-infrared spectrum of the primary star during a total secondary eclipse, and we use this to obtain disentangled spectra of both components. We determine spectral types of STA = M3.71 ± 0.69 and STB = M5.01 ± 0.73 and effective temperatures of Teff,A = 3190 ± 110 K and Teff,B = 3100 ± 110 K for the primary and secondary star, respectively. We also measure a metallicity of Fe/H]= +0.298 ± 0.080 for the system. We find that the system has a small, but significant, nonzero eccentricity of 0.0136 ± 0.0026. The K2 light curve shows a coherent variation at a period of 3.41315-0.00032 +0.00030 days, which is slightly longer than the orbital period, and which we demonstrate comes from the primary star. We interpret this as the rotation period of the primary. We perform a quantitative comparison between the Dartmouth stellar evolution models and the seven systems, including HATTR-318-007, that contain M dwarfs with 0.2M⊙ N < M < 0.5M⊙ N, have metallicity measurements, and have masses and radii determined to better than 5% precision. Discrepancies between the predicted and observed masses and radii are found for three of the systems. © 2018. The American Astronomical Society. All rights reserved.Item HATS-39b, HATS-40b, HATS-41b, and HATS-42b: Three Inflated Hot Jupiters and a Super-Jupiter Transiting F Stars(Oxford Univ Press) Bento, J.; Hartman, J. D.; Bakos, G. A.; Bhatti, W.; Csubry, Z.; Penev, Kaloyan; Bayliss, D.; de Val-Borro, M.; Zhou, G.; Brahm, R.; Espinoza, N.; Rabus, M.; Jordan, A.; Suc, V.; Ciceri, S.; Sarkis, P.; Henning, T.; Mancini, L.; Tinney, C. G.; Wright, D. J.; Durkan, S.; Tan, T. G.; Lazar, J.; Papp, I.; Sari, P.; 0000-0003-4464-1371 (Penev, K); Penev, KaloyanWe report the discovery of four transiting hot Jupiters from the HATSouth survey: HATS39b, HATS-40b, HATS-41b, and HATS-42b. These discoveries add to the growing number of transiting planets orbiting moderately bright (12.5 ≲ V ≲ 13.7) F dwarf stars on short (2-5 d) periods. The planets have similar radii, ranging from 1.33{_{0.20}^{+0.29}} R_J for HATS-41b to 1.58{_{-0.12} ^{+0.16}} R_J for HATS-40b. Their masses and bulk densities, however, span more than an order of magnitude. HATS-39b has a mass of 0.63 ± 0.13M(J), and an inflated radius of 1.57 ± 0.12 R-J, making it a good target for future transmission spectroscopic studies. HATS41b is a very massive 9.7 ± 1.6M_J planet and one of only a few hot Jupiters found to date with a mass over 5 M_J. This planet orbits the highest metallicity star ([Fe/H] = 0.470 ± 0.010) known to host a transiting planet and is also likely on an eccentric orbit. The high mass, coupled with a relatively young age (1.34{_{-0.51} ^{+0.31}} Gyr) for the host star, is a factor that may explain why this planet's orbit has not yet circularized.Item HATS-60b-HATS-69b: 10 Transiting Planets from HATSouth(IOP Publishing Ltd, 2019-02) Hartman, J. D.; Bakos, G. A.; Bayliss, D.; Bento, J.; Bhatti, W.; Brahm, R.; Csubry, Z.; Espinoza, N.; Penev, Kaloyan; Penev, KaloyanWe report the discovery of 10 transiting extrasolar planets by the HATSouth survey. The planets range in mass from the super-Neptune HATS-62b, with Mₚ < 0.179 Mⱼ, to the super-Jupiter HATS-66b, with Mₚ = 5.33 Mⱼ, and in size from the Saturn HATS-69b, with Rₚ = 0.94 Rⱼ, to the inflated Jupiter HATS-67b, with Rₚ = 1.69 Rⱼ. The planets have orbital periods between 1.6092 days (HATS-67b) and 7.8180 days (HATS-61b). The hosts are dwarf stars with masses ranging from 0.89 M⊙(HATS-69) to 1.56 M⊙ (HATS-64) and have apparent magnitudes between V = 12.276 ± 0.020 mag (HATS-68) and V = 14.095 ± 0.030 mag (HATS-66). The super-Neptune HATS-62b is the least massive planet discovered to date with a radius larger than Jupiter. Based largely on the Gaia DR2 distances and broadband photometry, we identify three systems (HATS-62, HATS-64, and HATS-65) as having possible unresolved binary star companions. We discuss in detail our methods for incorporating the Gaia DR2 observations into our modeling of the system parameters and into our blend analysis procedures.Item Hats-70b: A 13 MJ Brown Dwarf Transiting an A Star(IOP Publishing Ltd, 2019-01-02) Zhou, G.; Bakos, G. A.; Bayliss, D.; Bento, J.; Bhatti, W.; Brahm, R.; Csubry, Z.; Espinoza, N.; Hartman, J. D.; Henning, T.; Jordan, A.; Mancini, L.; Penev, Kaloyan; Rabus, M.; Sarkis, P.; Suc, V.; de Val-Borro, M.; Rodriguez, J. E.; Osip, D.; Kedziora-Chudczer, L.; Bailey, J.; Tinney, C. G.; Durkan, S.; Lazar, J.; Papp, I.; Sari, P.; 0000-0003-4464-1371 (Penev, K); Penev, KaloyanWe report the discovery of HATS-70b, a transiting brown dwarf at the deuterium burning limit. HATS-70b has a mass of M_{p} = 12.9{{-1.6}^{+1.8} M_{Jup} and a radius of R_{p} = 1.384_{{-0.074} {+0.079}} R_{Jup}, residing in a close-in orbit with a period of 1.89 days. The host star is a M⁎ = 1.78 ± 0.12 M_⊙ A star rotating at v sin I⁎ = 40.61{_{-0.35}}^{+0.32}} km s⁻¹ , enabling us to characterize the spectroscopic transit of the brown dwarf via Doppler tomography. We find that HATS-70b, like other massive planets and brown dwarfs previously sampled, orbits in a low projected-obliquity orbit with λ = {_{8.9}^{5.6°}}. The low obliquities of these systems is surprising given all brown dwarf and massive planets with obliquities measured orbit stars hotter than the Kraft break. This trend is tentatively inconsistent with dynamically chaotic migration for systems with massive companions, though the stronger tidal influence of these companions makes it difficult to draw conclusions on the primordial obliquity distribution of this population. We also introduce a modeling scheme for planets around rapidly rotating stars, accounting for the influence of gravity darkening on the derived stellar and planetary parameters.Item Kelt-19Ab: A P ~ 4.6-day Hot Jupiter Transiting a Likely Am Star with a Distant Stellar Companion(IOP Publishing Ltd, 2018-11-05) Siverd, Robert J.; Collins, Karen A.; Zhou, George; Quinn, Samuel N.; Gaudi, B. Scott; Stassun, Keivan G.; Johnson, Marshall C.; Penev, Kaloyan; Penev, KaloyanWe present the discovery of the giant planet KELT-19Ab, which transits the moderately bright (V similar to 9.9) A8V star TYC 764-1494-1 with an orbital period of 4.61 days. We confirm the planetary nature of the companion via a combination of. radial velocities, which limit the mass to less than or similar to 4.1 M-J (3 sigma), and a clear Doppler tomography signal, which indicates a retrograde projected spin-orbit misalignment of lambda = -179.7(-3.7)(+3.8) degrees. Global modeling indicates that the T-eff=7500. 110 K host star has M-star = 1.62(-0.20)(+0.25) M-star and R-star = 1.83 +/- 0.10 R-circle dot. The planet has a radius of R-P = 1.91 +/- 0.11 R-J and receives a stellar insolation flux of similar to 3.2 x 10(9) erg s(-1) cm(-2), leading to an inferred equilibrium temperature of T-eq similar to 1935 K assuming zero albedo and complete heat redistribution. With a v sin I-* = 84.8 +/- 2.0 km s(-1), the host. is relatively slowly rotating compared to other stars with similar effective temperatures, and it appears to be enhanced in metallic elements but deficient in calcium, suggesting that it is likely an Am star. KELT-19A would be the first detection of an Am host of a transiting planet of which we are aware. Adaptive optics observations of the system reveal the existence of a companion with late-G9V/early-K1V spectral type at a projected separation of approximate to 160 au. Radial velocity measurements indicate that this companion is bound. Most Am stars are known to have stellar companions, which are often invoked to explain the relatively slow rotation of the primary. In this case, the stellar companion is unlikely to have caused the tidal braking of the primary. However, it may have emplaced the transiting planetary companion via the Kozai-Lidov mechanism.Item KELT-22Ab: A Massive, Short-Period Hot Jupiter Transiting a Near-Solar Twin(IOP Publishing Ltd, 2019-01-21) Labadie-Bartz, Jonathan; Rodriguez, Joseph E.; Stassun, Keivan G.; Ciardi, David R.; Penev, Kaloyan; Johnson, Marshall C.; Gaudi, B. Scott; 0000-0003-4464-1371 (Penev, K); Penev, KaloyanWe present the discovery of KELT-22Ab, a hot Jupiter from the KELT-South survey. KELT-22Ab transits the moderately bright (V ~ 11.1) Sun-like G2V star TYC 7518-468-1. The planet has an orbital period of P = 1.3866529 ± 0.0000027 days, a radius of R_{P} = 1.285{_{-0.071}^{+0.12}} R_{J}, and a relatively large mass of M_{P} = 3.47{_{-0.14}^{+0.15}}, M_{J}. The star has R_{⋆} = 1.099{_{-0.046}^{0.079}} R_{⊙}, M_{⋆} = 1.092{_{-0.041}^{+0.045}} M_{⊙}, T_{eff} = 5767{_{-49}^{+50}} K, log g_{⋆} = 4.393{_{-0.060}^{+0.039}} (cgs), and [m/H] = +0.259{_{-0.083}^{+0.085}}; thus other than its slightly super-solar metallicity, it appears to be a near-solar twin. Surprisingly, KELT-22A exhibits kinematics and a Galactic orbit that are somewhat atypical for thin-disk stars. Nevertheless, the star is rotating rapidly for its estimated age, and shows evidence of chromospheric activity. Imaging reveals a slightly fainter companion to KELT-22A that is likely bound, with a projected separation of 6 '' (similar to 1400 au). In addition to the orbital motion caused by the transiting planet, we detect a possible linear trend in the radial velocity of KELT-22A, suggesting the presence of another relatively nearby body that is perhaps non-stellar. KELT-22Ab is highly irradiated (as a consequence of the small semimajor axis of a/R_{⋆}, and is mildly inflated. At such small separations, tidal forces become significant. The configuration of this system is optimal for measuring the rate of tidal dissipation within the host star. Our models predict that, due to tidal forces, the semimajor axis is decreasing rapidly, and KELT-22Ab is predicted to spiral into the star within the next Gyr.Item Spherically Symmetric Static Solutions in General Relativity(2021-12-01T06:00:00.000Z) Solanki, Rahulkumar; King, Lindsay J.; Stefan, Mihaela C.; Akbar, Mohammad; Kesden, Michael; Ishak-Boushaki, Mustapha; Penev, KaloyanThis thesis studies spherically symmetric static solutions in general relativity. The most general form of matter in general relativity compatible with staticity and spherical symmetry is anisotropic fluid. We study all possible algorithms that can generate all solutions of the anisotropic fluid system via quadrature using all possible pairs of the four basic functions of the system as input functions. We also study sub-algorithms that generate all solutions that are regular at the center and, for this, we revisit the conditions for central regularity for both isotropic and anisotropic systems and obtain all possible sets of equivalent initial conditions for regularity by combining the Einstein equations with the previouslyknown geometric conditions of regularity. Our study provides a reformulation of an existing algorithm for the system and provides its first regularity analysis. A surprisingly simple new algorithm for the anisotropic system follows from our study that aligns itself with the regularity conditions. This concordance enables us to find solutions that satisfy all the other hard-to-achieve conditions of physical acceptability. Anisotropy has increasingly been shown to be physically relevant in recent times. We keep the well-studied isotropic system as a special case and use it as a frame of reference for measuring the success of our study of the anisotropic system. We then study the hydrostatic equilibrium of static (an)isotropic fluid spheres. From the condition of hydrostatic equilibrium, we explore maps between (an)isotropic solutions with the same density profiles and develop solution-generating techniques to find new solutions from existing ones. We compare and give physical interpretations of several equilibrium configurations in terms of fluid variables and provide several examples where the solutiongenerating theorems can be utilized to find physically acceptable anisotropic solutions. This include a new exact solution that satisfies all physically desirable conditions. Finally, we study light propagation in Kottler, i.e., Schwarzschild-(anti-)de Sitter, spacetime. The metric of this spacetime is known in canonical coordinates and, unlike its Λ = 0 version (i.e, Schwarzschild metric), this metric was not known in isotropic coordinates (in which the constant-time hypersurfaces are flat). We obtain the Kottler metric in isotropic coordinates. This further enables us to plot the refractive indices of Kottler spacetime and show that the invariance of Snell’s law in ordinary geometric optics is analogous to projective equivalence in isotropic static coordinates. We conclude with a summary and some future directions.Item Study of Intrinsic Alignment of Galaxies in Recent Galaxy Surveys(2021-12-01T06:00:00.000Z) Pedersen, Eske M; Ishak-Boushaki, Mustapha; González, Juan E.; Kesden, Michael; Penev, Kaloyan; Da Silveira Rodrigues, Fabiano; King, Lindsay J.Weak lensing is one of the most promising new probes of cosmological parameters. However, it also comes with its own series of systematics and challenges to overcome. In this dissertation we will focus on our work done to isolate the astrophysical systematic effect known as intrinsic alignment of galaxies. We first introduce the methodology and underlying theory that gave rise to the field of weak gravitational lensing, explaining how minuscule changes in the shapes of distant galaxies can be used to obtain better constraints on the matter distribution and the makeup of our entire universe. Then we introduce the idea that galaxies are not isolated objects, but rather are located inside clusters of galaxies or along gas-rich filaments of the large scale structure of the universe. This leads to a systematic effect in the form of the galaxy shapes being distorted prior to lensing, because they intrinsically align with the large scale structure around them. This effect causes either false negatives or false positives when interpreted as weak lensing distortions in observations. Intrinsic alignment of galaxies was first detected about a decade and a half ago, and since then a few different approaches have been suggested to mitigate this. Our work is focused on the idea of using the extra information like unused correlations available within modern cosmological surveys to isolate these intrinsic alignment signals. This provides us with the dual advantages of getting rid of a systematic effect but also gives the possibility of studying the intrinsic alignment itself in more detail. Our work has focused on the development of analysis tools for this separation and the subsequent application of these tools to detect of intrinsic alignment of galaxies. This is done in anticipation of the upcoming Vera Rubin Observatory’s Legacy Survey of Space and Time (LSST). The tools described in this dissertation were made specifically to be ready for this survey and were developed as extensions to the analysis tools being developed for the LSST by its Dark Energy Science Collaboration (DESC). Since LSST has not yet begun, we have applied these tools to two earlier surveys: The Kilo Degree Survey (KiDS)’s data release of approximately 450 square degrees and the Dark Energy Survey (DES)’s year one data release. In both cases we have found strong signs of intrinsic alignment using our self-calibration analysis. We also showed how we can use this method to handle both intrinsic alignment in galaxy-galaxy lensing and in cosmic shear correlations. This has strong implications for constraining the physics of galaxy evolution with LSST.Item Synthesis and Bioactivity Evaluation of KDM4 Inhibitors in Prostate Cancer Cells(December 2022) Smith, Tristan; Ahn, Jung Mo; Penev, Kaloyan; Smaldone, Ronald A.; D'Arcy, Sheena; Stefan, Mihaela C.The need for alternative therapeutic targets has grown due to the stagnating progress of treatment for metastatic prostate cancer with activity independent of the androgen receptor. Inhibition of histone lysine demethylases belonging to the KDM4 subfamily are of significant interest due to their aberrant expression and role in castration-resistant prostate cancer. This dissertation presents the design, synthesis, and biochemical evaluation for a library of 8-hydroxyquinoline-based derivatives of B3, a KDM4 inhibitor that has previously demonstrated therapeutic potential. Motivated by the search for improved efficacy for KDM4 inhibition in prostate cancer, the first investigation highlights the structure-activity relationship discovered from modifying the phenylpropyl moiety of B3. Screening a comprehensive list of different chemical groups revealed several with improved inhibitor activity and stability. Continuing our search for improved efficacy, the second investigation explored augmentation of the benzamide moiety of B3 that led to the identification of a new lead inhibitor using 4-(3-methoxypropyl)morpholine. This modification to B3 led to the desired cytotoxicity to tumor viability during in vitro MTT assays and in vivo murine studies.Item Synthesis and Bioactivity Evaluation of KDM4 Inhibitors in Prostate Cancer Cells(December 2022) Smith, Tristan; Ahn, Jung Mo; Penev, Kaloyan; Smaldone, Ronald A.; D'Arcy, Sheena; Stefan, Mihaela C.The need for alternative therapeutic targets has grown due to the stagnating progress of treatment for metastatic prostate cancer with activity independent of the androgen receptor. Inhibition of histone lysine demethylases belonging to the KDM4 subfamily are of significant interest due to their aberrant expression and role in castration-resistant prostate cancer. This dissertation presents the design, synthesis, and biochemical evaluation for a library of 8-hydroxyquinoline-based derivatives of B3, a KDM4 inhibitor that has previously demonstrated therapeutic potential. Motivated by the search for improved efficacy for KDM4 inhibition in prostate cancer, the first investigation highlights the structure-activity relationship discovered from modifying the phenylpropyl moiety of B3. Screening a comprehensive list of different chemical groups revealed several with improved inhibitor activity and stability. Continuing our search for improved efficacy, the second investigation explored augmentation of the benzamide moiety of B3 that led to the identification of a new lead inhibitor using 4-(3-methoxypropyl)morpholine. This modification to B3 led to the desired cytotoxicity to tumor viability during in vitro MTT assays and in vivo murine studies.Item The Averaging Problem in Cosmology and Macroscopic Gravity(2022-08-01T05:00:00.000Z) Agashe, Anish; Ishak-Boushaki, Mustapha; Gevorgyan, Vladimir; King, Lindsay; Kesden, Michael; Penev, Kaloyan; Akbar, MohammadThe dynamics of the universe are traditionally modelled by employing cosmological so- lutions to the Einstein field equations. In these solutions, the matter distribution is taken to be averaged over cosmological scales, and hence, the Einstein tensor needs to be av- eraged as well. To construct such an averaged theory of gravity, one needs a covariant averaging procedure for tensor fields. Macroscopic gravity (MG) is one such theory. It gives the macroscopic Einstein field equations (mEFEs) where the effects due to averag- ing are encapsulated in a correction term, the so-called back-reaction. This additional term accounts for the non-commutativity between the averaging operation and the calculation of Einstein tensor. In this dissertation, we analyse how to deal with inhomogeneities within macroscopic gravity. First, we model the inhomogeneities as linear perturbations around the spa- tially homogeneous Friedmann-Robertson-Lemaître-Walker (FLRW) geometry. Then, we analyse exact inhomogeneous models with plane and spherically symmetric geometries. We calculate the back-reaction in these models and analyse how it modifies observations done within them. First, we explore the application of the MG formalism to an almost-FLRW model. Namely, we find solutions to the field equations of MG taking the averaged universe to be almost- FLRW modelled using a linearly perturbed FLRW metric. We study several solutions with different functional forms of the metric perturbations including plane waves ansatzes. We find that back-reaction terms are present not only at the background level but also at perturbed level, reflecting the non-linear nature of the averaging process. To analyse how observations get modified by the back-reaction, we derive the expres- sions for distance measures in MG. We analyse two cases. In the first one, the back- reaction modifies distances only through the expansion history. In the second one, the back-reaction density parameter enters the distance formulae in such a way that, phe- nomenologically, it is degenerate with a spatial curvature. Turning to the perturbations, we derive an equation for growth of structure and analyse how back-reaction modifies the linear growth rate. Thus, the averaging effect can extend to both the expansion and the growth of structure in the universe. Then, we turn our attention to inhomogeneous models with plane and spherically sym- metric geometries. We calculate the MG correction term for such models and find that it takes the form of an anisotropic fluid with a qualitative behaviour of an effective cur- vature in the field equations. We categorise the solutions according to the source for the space-time – vacuum, dust and perfect fluid. Within these three categories, we treat, in detail, the cases of the static spherically symmetric vacuum solution (Schwarzschild exte- rior), the static spherically symmetric perfect fluid solutions (Schwarzschild interior and Tolman VII) and the non-static spherically symmetric dust solution (Lemaître-Tolman- Bondi (LTB)). This is a first step towards analysing back-reaction in inhomogeneous cos- mology with MG.