Physical Sciences and Mathematics Commons^™

Perspective Sky: A New Architectural Typology For Astronomy, Brendan Lydic

Bachelor of Architecture Theses - 5th Year

This thesis aims to reconnect modern humans to the night sky and the universe around us. A connection that has been lost to a multitude of barriers and distractions. Physical barriers like air and light pollution, and distractions like technology and overwhelming world events. I aim to restore this connection by creating a new architectural typology for the observation of and education about the night sky, the cosmos, and astronomy. It will serve as a site of pilgrimage, where visitors of all ages can re-engage with the stars and reintroduce themselves to the perspective of our ancestors. The questions I …

Energy Requirements For Abiotic Production Of Phosphorous Compounds At The Ice-Schreibersite Interface, Lindsay M. Hicks

Symposium of Student Scholars

Energy Requirements for Abiotic Production of Phosphorous Compounds at the

Ice-Schreibersite Interface

The Abbott-Lyon Lab is investigating the chemistry at the interface of simple ices and a meteoritic mineral analogue. Phosphorous is a key component of numerous biomolecules necessary for life. Lack of an abundance of biologically accessible mineral sources of phosphates on Earth, termed “The Phosphorous Problem,” has led some origin-of-life scientists to look to extraterrestrial sources like meteoritic metal phosphides as possible sources of available phosphates. Schreibersite (Fe₂NiP) is a common mineral in iron meteorites and a plausible source of biologically accessible phosphorous. This study will …

Mineral-Surface Chemistry Of Hydroxyapatite And Urea-Rich Solutions, Estefania Garcia

Master of Science in Chemical Sciences Theses

On this planet the development of life requires six essential elements: C, H, O, N, P, and S. These elements are present in gaseous form, with the exception of phosphorus, which is primarily found in solid mineral sources. Phosphorus in biological systems is significant through its involvement in metabolic functions (e.g., Coenzyme A), cell structure (i.e., phospholipid membranes), and genetic storage/transfer (i.e., phosphodiester bonds in DNA and RNA). However, an ambiguity remains with the assimilation of phosphorus in biological systems, caused by its habitual presence in insoluble phosphate mineral sources. Recent research has found that insoluble phosphate …

Magnetic Fields Threading Black Holes: Restrictions From General Relativity And Implications For Astrophysical Black Holes, David Garofalo

Faculty and Research Publications

The idea that black hole spin is instrumental in the generation of powerful jets in active galactic nuclei and X-ray binaries is arguably the most contentious claim in black hole astrophysics. Because jets are thought to originate in the context of electromagnetism, and the modeling of Maxwell fields in curved spacetime around black holes is challenging, various approximations are made in numerical simulations that fall under the guise of ‘ideal magnetohydrodynamics’. But the simplifications of this framework may struggle to capture relevant details of real astrophysical environments near black holes. In this work, we highlight tension between analytic and numerical …

Possible Evolution Of Supermassive Black Holes From Fri Quasars, Matthew I. Kim, Damian J. Christian, David Garofalo, Jaclyn D'Avanzo

Faculty and Research Publications

We explore the question of the rapid buildup of black hole mass in the early universe employing a growing black hole mass-based determination of both jet and disc powers predicted in recent theoretical work on black hole accretion and jet formation. Despite simplified, even artificial assumptions about accretion and mergers, we identify an interesting low probability channel for the growth of one billion solar mass black holes within hundreds of millions of years of the big bang without appealing to super Eddington accretion. This result is made more compelling by the recognition of a connection between this channel and an …

Understanding The Surface Induced Phosphorylation Of Prebiotic Molecules By Schreibersite, Danna Qasim

Master of Science in Chemical Sciences Theses

The study of the surface of a meteoritic mineral, schreibersite (Fe,Ni)₃P, was investigated to provide insight into the role of the mineral’s surface in aqueous-phase phosphorylation reactions. The optimization of a custom-designed ultrahigh vacuum (UHV) apparatus and Fe₂NiP (schreibersite) surface was performed to permit surface science analysis. The bare surface was characterized by scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS), which showed some oxidation and segregation of phosphorous within the near-surface region. The interaction and/or reaction of water (H₂O), methanol (CH₃OH), formic acid …

Scale Invariant Jet Suppression Across The Black Hole Mass Scale, David Garofalo, Chandra B. Singh

Faculty and Research Publications

We provide a schematic framework for understanding observations of jet suppression in soft state black hole X-ray binaries based on the Blandford-Payne process and the net magnetic flux threading the black hole. Due to the geometrical thinness of soft state disks, mass-loading of field lines is ineffective compared to both geometrically thick disks as well as thin disks with greater black hole threading flux, a simple physical picture that allows us to understand the weakness of jets in radiatively efficient thin disks accreting in the prograde direction around high-spinning black holes. Despite a simplicity that forbids insights into the complexity …

Reconciling Ag-Star Formation, The Soltan Argument, And Meier's Paradox, David Garofalo, Matthew I. Kim, Damian J. Christian, Emily Hollingworth

Faculty and Research Publications

We provide a theoretical context for understanding the recent work of Kalfountzou et al. showing that star formation is enhanced at lower optical luminosity in radio-loud quasars. Our proposal for coupling the assumption of collimated FRII quasar-jet-induced star formation with lower accretion optical luminosity also explains the observed jet power peak in active galaxies at higher redshift compared to the peak in accretion power, doing so in a way that predicts the existence of a family of radio-quiet active galactic nuclei associated with rapidly spinning supermassive black holes at low redshift, as mounting observations suggest. The relevance of this work …

Models Of Time Travel And Their Consequences, Antonio M. Mantica

Oglethorpe Journal of Undergraduate Research

How do we travel through time? We know that we can move forward in it (we have no choice), but can we jump forward in time? Can we go backward in time? It also gives rise to other troubling questions: is time measurable in distinct increments, or does it flow continuously? In "Models of Time Travel and their Consequences," Antonio Mantica walks the reader through current understandings of how time functions in Einstein's universe and proposes three distinct models to explain it. Following that, he provides a list of experiments to credit or discredit the models. Appropriate for audiences of …

Symmetry And The Arrow Of Time In Theoretical Black Hole Astrophysics, David Garofalo

Faculty and Research Publications

While the basic laws of physics seem time-reversal invariant, our understanding of the apparent irreversibility of the macroscopic world is well grounded in the notion of entropy. Because astrophysics deals with the largest structures in the Universe, one expects evidence there for the most pronounced entropic arrow of time. However, in recent theoretical astrophysics work it appears possible to identify constructs with time-reversal symmetry, which is puzzling in the large-scale realm especially because it involves the engines of powerful outflows in active galactic nuclei which deal with macroscopic constituents such as accretion disks, magnetic fields, and black holes. Nonetheless, the …

The Ptolemaic System: A Detailed Synopsis, John Cramer Dr.

Oglethorpe Journal of Undergraduate Research

The Ptolemaic System, constructed by Claudius Ptolemeus (the Latin form of his name), was the most influential of all Earth centered cosmological systems. His ingenious and creative work is primarily recorded in his book The Mathematical Systematic Treatise which the Arabs characterized as “the greatest” and, in so doing, gave the book its most used name, Almagest.

The Copernican System: A Detailed Synopsis, John Cramer Dr.

Oglethorpe Journal of Undergraduate Research

Dissatisfied with the problems of the geocentric system inherited from Claudius Ptolemy, Nicholas Copernicus began the change from geocentrism to heliocentrism. His eponymous system was expounded first in the Commentariolus (written about 1508 and circulated privately in manuscript form) and then more fully and finally in his book, De Revolutionibus Orbium Coelestium (On the Revolutions of the Celestial Orbs) published as he lay dying in 1543.

Constraints Of The Radio-Loud/Radio-Quiet Dichotomy From The Fundamental Plane, David Garofalo, Matthew I. Kim, Damian J. Christian

Faculty and Research Publications

The Fundamental Plane for black hole activity constitutes a tight correlation between jet power, X-ray luminosity, and black hole mass. Under the assumption that a Blandford–Znajek-type mechanism, which relies on black hole spin, contributes non-negligibly to jet production, the sufficiently small scatter in the Fundamental Plane shows that black hole spin differences of |Δa| ∼ 1 are not typical among the active galactic nuclei population. If – as it seems – radio-loud and radio-quiet objects are both faithful to the Fundamental Plane, models of black hole accretion in which the radio-loud/radio-quiet dichotomy is based on a spin dichotomy of a∼1/a∼0, …

Shadows In Time: A Study Of Temporal Metaphysics Through Hard Science Fiction And Its Restrictions On The Past And Future, Lindsey E. Mitchell

Oglethorpe Journal of Undergraduate Research

Through a series of essays, this body of work explores the varying theories concerning the nature of time and how each theory affects the possibility and outcome of time travel. Following these essays, a collection of short stories focuses on what the author considers the most probable theories concerning time and expands on how they might affect a time traveler's decisions and fate.

The Jet-Disk Connection: Evidence For A Reinterpretation In Radio-Loud And Radio-Quiet Active Galactic Nuclei, David Garofalo

Faculty and Research Publications

To constrain models of the jet-disc connection, we explore Eddington ratios reported in Foschini (2011) and interpret them in relation to the values in Sikora et al. across the active galactic nuclei population from radio loud quasars, their flat spectrum radio quasar subclass, the recently discovered gamma-ray loud narrow-line type 1 Seyfert galaxies, Fanaroff-Riley type I (FRI) radio galaxies and radio quiet quasars of the Palomar Green survey. While appeal to disc truncation in radiatively inefficient flow appears to explain the observed inverse relation between radio loudness and Eddington ratio in radio loud and radio quiet quasars, FR I objects, …

Retrograde Versus Prograde Models Of Accreting Black Holes, David Garofalo

Faculty and Research Publications

There is a general consensus that magnetic fields, accretion disks, and rotating black holes are instrumental in the generation of the most powerful sources of energy in the known universe. Nonetheless, because magnetized accretion onto rotating black holes involves both the complications of nonlinear magnetohydrodynamics that currently cannot fully be treated numerically, and uncertainties about the origin of magnetic fields that at present are part of the input, the space of possible solutions remains less constrained. Consequently, the literature still bears witness to the proliferation of rather different black hole engine models. But the accumulated wealth of observational data is …

Next-To-Next-To-Leading Soft-Gluon Corrections For The Top Quark Cross Section And Transverse Momentum Distribution, Nikolaos Kidonakis

Faculty and Research Publications

I present results for top quark production in hadronic collisions at LHC and Tevatron energies. The soft-gluon corrections to the differential cross section are resummed at next-to-next-to-leading-logarithm accuracy via the two-loop soft anomalous dimension matrices. Approximate next-to-next-to-leading-order differential and total cross sections are calculated. Detailed theoretical predictions are shown for the t (t) over bar cross section and the top quark p(T) distribution at the Tevatron and the LHC.

Random Flows And Diagnostics Of Turbulence In The High Latitude Cirrus, Steven N. Shore, Ted N. Larosa, Raymond J. Chastain, Loris Magnani

Faculty and Research Publications

Aims: We present an analysis of the exceptionally turbulent velocity field in the high Galactic latitude cirrus cloud MBM 3. As in the other translucent clouds in our study (MBM 16 and MBM 40), there is no evidence for internal star formation. However, the large scale velocity variation in this cloud is more pronounced. Methods: We have mapped the cloud in 12CO and 13CO (1-0) at high spatial (0.03 pc) and velocity (0.06 km s-1) resolution. We constructed several velocity probability density functions (PDFs), estimated the turbulent transfer rate, and analyzed the linewidths as a function of the size of …

The Strength And Structure Of The Galactic Center Magnetic Field, Ted La Rosa, Steven N. Shore, T. Joseph W. Lazio, Namir E. Kassim

Faculty and Research Publications

This paper summarizes recently obtained, strong evidence for a weak global field in the Galactic center (GC): the existence of a large-scale region of diffuse, low-frequency, nonthermal emission coincident with the central molecular zone. The overall energetics of this emission, considered along with constraints on GC cosmic ray energy density and diffusion, indicate clearly that the magnetic field pervading this region is ∼ 10 μG. For completeness, additional points on the orientation of the GC nonthermal filaments, rotation measures of extragalactic sources seen through the GC, and comparison with other normal spiral galaxies are also reviewed.

Evidence Of A Weak Galactic Center Magnetic Field From Diffuse Low-Frequency Nonthermal Radio Emission, Ted La Rosa, Crystal L. Brogan, Steven N. Shore, T. Joseph Lazio, Namir E. Kassim, Michael E. Nord

Faculty and Research Publications

New low-frequency 74 and 330 MHz observations of the Galactic center (GC) region reveal the presence of a large-scale (6° × 2°) diffuse source of nonthermal synchrotron emission. A minimum-energy analysis of this emission yields a total energy of ~(phi4/7f3/7) × 1052 ergs and a magnetic field strength of ~6(phi/f)2/7 μG (where phi is the proton to electron energy ratio and f is the filling factor of the synchrotron emitting gas). The equipartition particle energy density is 1.2(phi/f)2/7 eV cm-3, a value consistent with cosmic-ray data. However, the derived magnetic field is several orders of magnitude below the 1 mG …

High-Resolution, Wide-Field Imaging Of The Galactic Center Region At 330 Mhz, Michael E. Nord, T. Joseph W. Lazio, Namir E. Kassim, Scott D. Hyman, Ted W. La Rosa, Crystal L. Brogan, Nebojsa Duric

Faculty and Research Publications

We present a wide-field, subarcminute-resolution VLA image of the Galactic center region at 330 MHz. With a resolution of ~7'' × 12'' and an rms noise of 1.6 mJy beam^-1, this image represents a significant increase in resolution and sensitivity over the previously published VLA image at this frequency. The improved sensitivity has more than tripled the census of small-diameter sources in the region, has resulted in the detection of two new nonthermal filaments (NTFs), 18 NTF candidates, and 30 pulsar candidates, reveals previously known extended sources in greater detail, and has resulted in the first detection of …

New Nonthermal Filaments At The Galactic Center: Are They Tracing A Globally Ordered Magnetic Field?, Ted La Rosa, Michael E. Nord, Joseph W. Lazlo, Namir E. Kassim

Faculty and Research Publications

New high-resolution, wide-field 90 cm VLA observations of the Galactic center (GC) region by Nord and coworkers have revealed 20 nonthermal filament (NTF) candidates. We report 6 cm polarization observations of six of these. All of the candidates have the expected NTF morphology, and two show extended polarization, confirming their identification as NTFs. One of the new NTFs appears to be part of a system of NTFs located in the Sgr B region, 64 pc in projection north of Sgr A. These filaments cross the Galactic plane with an orientation similar to the filaments in the Galactic center radio arc. …

Complex Multiplication Symmetry Of Black Hole Attractors, Monika Lynker, Vipul Periwal, Rolf Schimmrigk

Faculty and Research Publications

We show how Moore’s observation, in the context of toroidal compactifications in type IIB string theory, concerning the complex multiplication structure of black hole attractor varieties, can be generalized to Calabi-Yau compactifications with finite fundamental groups. This generalization leads to an alternative general framework in terms of motives associated to a Calabi-Yau variety in which it is possible to address the arithmetic nature of the attractor varieties in a universal way via Deligne’s period conjecture.

High Resolution, High Sensitivity Imaging Of The Galactic Center At 330 Mhz, Michael E. Nord, Crystal L. Brogan, Scott D. Hyman, T. Joseph W. Lazio, Namir E. Kassim, Ted N. Larosa, K. Anantharamaiah, Nebojsa Duric

Faculty and Research Publications

We present results derived from a wide field, sub-arcminute resolution VLA image of the Galactic Center region at 330 MHz (λ = 90 cm). With a resolution of ∼7″ × 12″ and an rms noise of 1.6 mJy beam⁻¹, this image represents a significant increase in resolution and sensitivity over the previously published VLA image at this frequency (eg. LaRosa et al. 2000). The improvement in sensitivity has significantly increased the census of small diameter sources in the region, resulted in the detection of two new Non-Thermal Filaments (NTFs) and 18 new NTF candidates, and resulted in …

The Galactic Center Nonthermal Filaments: Recent Observations And Theory, Ted La Rosa, Michael E. Nord, T. Joseph W. Lazio, Steven N. Shore, Namir E. Kassim

Faculty and Research Publications

The large-scale topology and strength of the Galactic Center magnetic field have been inferred from radio imaging of the nonthermal filaments (NTFs). These objects, which seem to be unique to the Galactic center, are defined by extreme aspect ratios and a high degree of polarization. Recent high resolution, wide-field VLA imaging of the GC at 90 cm has revealed new candidate NTFs with a wide range of orientations relative to the Galactic plane. We present follow up 6 cm polarization observations of 6 of these candidates and confirm 4 as new NTFs. Together the new 90 and 6 cm results …

Mechanisms For The Origin Of Turbulence In Non-Star-Forming Clouds: The Translucent Cloud Mbm 40, Steven N. Shore, Loris Magnani, Ted La Rosa, Meredith N. Mccarthy

Faculty and Research Publications

We present a multiline, high spatial and velocity resolution CO, H I, and IRAS 100 μm study of the high-latitude, low-mass, non-star-forming, translucent molecular cloud MBM 40. The cloud mass is distributed into two ridges, or filaments, that form a hairpin structure. Velocity channel maps indicate a highly ordered flow in the molecular gas, with the northeastern part of the filament moving away from and the southwestern filament moving toward the observer relative to the mean cloud radial velocity. Significant changes in emissivity occur over 0.03 pc, indicating large transverse density gradients along the ridges. However, the velocity field appears …

Black Hole Attractor Varieties And Complex Multiplication, Monika Lynker, Vipul Periwal, Rolf Schimmrigk

Faculty and Research Publications

Black holes in string theory compactified on Calabi-Yau varieties a priori might be expected to have moduli dependent features. For example the entropy of the black hole might be expected to depend on the complex structure of the manifold. This would be inconsistent with known properties of black holes. Supersymmetric black holes appear to evade this inconsistency by having moduli fields that flow to fixed points in the moduli space that depend only on the charges of the black hole. Moore observed in the case of compactifications with elliptic curve factors that these fixed points are arithmetic, corresponding to curves …

Modeling The Galactic Center Nonthermal Filaments As Magnetized Wakes, Russell B. Dahlburg, Giorgio Einaudi, Ted N. La Rosa, Steven N. Shore

Faculty and Research Publications

We simulate the Galactic center nonthermal laments as magnetized wakes formed dynamically from amplification of a weak ( tens of l G) global magnetic field through the interaction of molecular clouds with a Galactic center wind. One of the key issues in this cometary model is the stability of the lament against dynamical disruption. Here we show two-dimensional MHD simulations for interstellar conditions that are appropriate for the Galactic center. The structures eventually disrupt through a shear-driven nonlinear instability but maintain coherence for lengths up to 100 times their width as observed. The final instability, which destroys the lament through …

A New System Of Parallel Isolated Nonthermal Filaments Near The Galactic Center: Evidence For A Local Magnetic Field Gradient, Ted N. La Rosa, Joseph W. Lazio, Nasir E. Kassim

Faculty and Research Publications

We report the discovery of a system of isolated nonthermal filaments approximately 0fdg5 northwest (75 pc in projection) of Sgr A. Unlike other isolated nonthermal filaments which show subfilamentation, braiding of subfilaments, and flaring at their ends, these filaments are simple linear structures and more closely resemble the parallel bundled filaments in the Galactic center radio arc. However, the most unusual feature of these filaments is that the 20/90 cm spectral index uniformly decreases as a function of length, in contrast to all other nonthermal filaments in the Galactic center. This spectral gradient may not be due to simple particle …

A Wide Field 90 Cm Vla Image Of The Galactic Center Region, Ted La Rosa, Namir E. Kassim, Joseph W. Lazlo, Scott B. Hyman

Faculty and Research Publications

We present a wide-field, high dynamic range, high-resolution, long-wavelength (lambda = 90 cm) VLA image of the Galactic center region. The image is centered on Sgr A, covers an area of 4 degrees x 5 degrees with an angular resolution of 43 ", and has a rms sensitivity of approximate to 5 mJy beam-l. The image was constructed from archival (1989 and 1991) VLA data of Pedlar et al. and Anantharamaiah et al. using new three-dimensional image restoration techniques. These three-dimensional imaging techniques resolve the problem of non-coplanar baselines encountered at long wavelengths and yield distortion-free imaging of far-field sources …