Physical Sciences and Mathematics Commons^™

Elasticity Of Cylindrical Black Holes, Conrad Pearson

Physics

Black holes are regions of strong gravity, and are often regarded as behaving like drops of fluid. When this line of thought is applied to cylindrical black holes (black cylinders), a mapping can be made between known instabilities for black cylinders and ordinary fluid cylinders. However, this known correlation is increasingly less accurate for lower spatial dimensions, and I seek to correct this discrepancy in this thesis. By considering soft solids instead of pure fluids, elastic energy can be included, which brings us closer to a direct comparison. In improving this mapping, it becomes possible to better understand the behavior …

Large-Scale Outflows In Luminous Qsos Revisited: The Impact Of Beam Smearing On Agn Feedback Efficiencies, Bernd Husemann, Julia Scharwächter, Vardha N. Bennert, V. Manieri, Jong-Hak Woo, Darshan Kakkad

Physics

Context. Feedback from active galactic nuclei (AGN) is thought to play an important role in quenching star formation in galaxies. However, the efficiency with which AGN dissipate their radiative energy into the ambient medium remains strongly debated.

Aims. Enormous observational efforts have been made to constrain the energetics of AGN feedback by mapping the kinematics of the ionized gas on kpc scale. We study how the observed kinematics and inferred energetics are affected by beam smearing of a bright unresolved narrow-line region (NLR) due to seeing.

Methods. We re-analyse optical integral-field spectroscopy of a sample of twelve luminous unobscured quasi-stellar …

Community Outreach With Play-Doh® Electronics, Thomas J. Bensky, William Bensky

Physics

It never fails: you’re in your office and the phone rings. Your department head says, “Hi! Fifty kids are coming to campus in 30 minutes. Can you meet with them and give them a one-hour hands-on activity that will make them excited about physics?” Likely you’ll run to your demonstration room and grab anything that’ll generate a bright light or cause something to explode or levitate, right? In recent years, we’ve taken a more systematic approach to hosting visitors by developing a ready-to-go hands-on activity that provides opportunities for learning about DC electric circuits.

The Close Agn Reference Survey (Cars): Mrk 1018 Returns To The Shadows After 30 Years As A Seyfert 1, R. E. Mcelroy, Bernd Husemann, S. M. Croom, T. A. Davis, Vardha N. Bennert, G. Busch, F. Combes, A. Eckart, M. Perez-Torres, M. Powell, J. Scharwächter, G. R. Tremblay, T. Urrutia

Physics

We report the discovery that the known “changing look” AGN Mrk 1018 has changed spectral type for a second time. New VLT-MUSE data taken in 2015 as part of the Close AGN Reference Survey (CARS) shows that the AGN has returned to its original Seyfert 1.9 classification. The CARS sample is selected to contain only bright type 1 AGN, but Mrk 1018’s broad emission lines and continuum, typical of type 1 AGN, have almost entirely disappeared. We use spectral fitting of the MUSE spectrum and previously available spectra to determine the drop in broad line flux and the Balmer decrement. …

Environmental And Economic Implications Of Alternative Cruise Ship Pathways In Bermuda, Sarah E. Lester, Crow White, Kevin Mayall, Ryan K. Walter

Physics

As the cruise ship industry moves towards ever larger vessels, many tourist destinations are faced with dilemmas about how to accommodate the latest generation of ships, which require deeper and wider shipping pathways. The location of nearshore shipping channels traveled by cruise ships has important environmental and economic implications, as dredging larger lanes damages habitat, ship traffic produces sediment plumes that can smother adjacent sensitive habitats (e.g., coral reefs, seagrass beds), and dredging costs vary spatially. These environmental and economic costs should ideally be evaluated in the context of projected benefits from increased tourism. To inform decision-making on cruise ship …

About Agn Ionization Echoes, Thermal Echoes, And Ionization Deficits In Low Redshift Lyman-Alpha Blobs, Mischa Schirmer, Sangeeta Malhotra, Nancy A. Levenson, Hai Fu, Rebecca L. Davies, William Keel, Paul Torrey, Vardha Nicola Bennert, Anna Pancoast, James E. H. Turner

Physics

We report the discovery of 14 Lyα blobs (LABs) at z ∼ 0.3, existing at least 4–7 billion years later in the Universe than all other LABs known. Their optical diameters are 20–70 kpc, and GALEX data imply Lyα luminosities of (0.4–6.3) × 10⁴³ erg s⁻¹. Contrary to high-z LABs, they live in low-density areas. They are ionized by AGN, suggesting that cold accretion streams as a power source must deplete between z = 2 and 0.3. We also show that transient AGN naturally explain the ionization deficits observed in many LABs. Their Lyα and X-ray …

Spontaneous Parametric Down-Conversion In A Beta Barium Borate Crystal, Nicholas Williams

Physics

No abstract provided.

Black Holes Modeled As Fluid Droplets On Membranes, Anthony Bardessono

Physics

No abstract provided.

Characterizing Kepler Objects Of Interest Using The Algorithm Exonest, Bertrand Carado

Physics

Recent observations across the galaxy have led to the conclusion that there exist many different extrasolar systems. Using photometric effects, the amount of data that has been produced on exoplanets has significantly increased and will continue to rise. Finding new methods of data analysis to broaden the spectrum of research has therefore become a necessity. Exonest is an algorithm currently in development that uses Bayesian methods, and notably nested sampling, to infer characteristics about an exoplanet from its observed light curve.

In this paper, Exonest was tested by being used to study three extra-solar systems: each containing a single confirmed …

The Utilization Of Exonest In Characterizing Kepler Objects, Nicole Wallack

Physics

With the first detection of an exoplanet, came the study of methods to detect and characterize additional planets. Multiple methods for finding exoplanets were developed, including transit methods. When a star’s flux is being observed for an extended period of time and a slight dip in the relative flux is seen periodically, this may be evidence of a planet passing in front of the star and blocking out a portion of the received flux. It is this method that is employed by the Kepler spacecraft. Kepler observes approximately 100,000 stars looking for periodic decreases in stellar fluxes. From the produced …

Spontaneous Parametric Down Conversion Of Photons Through Β-Barium Borate, Luke Horowitz

Physics

An apparatus for detecting pairs of entangled 405nm photons that have undergone Spontaneous Parametric Down Conversion through β-Barium Borate is described. By using avalanche photo-diodes to detect the low-intensity converted beam and a coincidence module to register coincident photons, it is possible to create an apparatus than can be used to perform quantum information experiments under a budget appropriate for an undergraduate physics lab.

Teaching Numerical Methods In The Context Of Galaxy Mergers, Maria Kourjanskaia

Physics

Methods of teaching numerical methods to solve ordinary differential equations in the context of galaxy mergers were explored. The research published in a paper by Toomre and Toomre in 1972 describing the formation of galactic tails and bridges from close tidal interactions was adapted into a project targeting undergraduate physics students. Typically undergraduate physics students only take one Computational Physics class in which various techniques and algorithms are taught. Although it is important to study computational physics techniques, it is just as important to apply this knowledge to a problem that is representative of what computational physics researchers are investigating …

Modeling The Sps Feedback And Feedforward Systems For Improved Performance, Jake Hargrove

Physics

The Super Proton Synchrotron (SPS) is the last link in the chain of accelerators providing protons to the Large Hadron Collider (LHC). The SPS is currently the limiting factor on the maximum number of protons and thus collisions in the LHC. The SPS upgrade is under way to expand the discovery potential of the LHC. The accelerating system — Radio Frequency (RF) — is being improved. Models of the SPS RF feedback systems were developed. These models could assist with design choices, evaluating the upgraded system performance, and anticipate limitations and issues.

Broad HΒ Emission-Line Variability In A Sample Of 102 Local Active Galaxies, Jordan Runco, Maren Cosens, Vardha Nicola Bennert, Bryan Scott, S. Komossa, Matthew A. Malkan, Mariana S. Lazarova, Matthew W. Auger, Tommaso Treu, Daeseong Park

Physics

A sample of 102 local (0.02 ≤ z ≤ 0.1) Seyfert galaxies with black hole masses M_BH > 10⁷M_⊙ was selected from the Sloan Digital Sky Survey (SDSS) and observed using the Keck 10 m telescope to study the scaling relations between M_BH and host galaxy properties. We study profile changes of the broad Hβ emission line within the three to nine year time frame between the two sets of spectra. The variability of the broad Hβ emission line is of particular interest, not only because it is used to estimate M_BH, …

Observations Of Nonlinear Internal Waves At A Persistent Coastal Upwelling Front, Ryan K. Walter, Marek Stastna, C. Brock Woodson, Stephen G. Monismith

Physics

We collected high-resolution observations of nonlinear internal waves (NLIWs) at a persistent upwelling front in the shallow coastal environment (~20 m) of northern Monterey Bay, CA. The coastal upwelling front forms between recently upwelled waters and warmer stratified waters that are trapped in the bay (upwelling shadow). The front propagates up and down the coast in the along-shore direction as a buoyant plume front due to modulation by strong diurnal wind forcing. The evolution of the coastal upwelling front, and the subsequent modulation of background environmental conditions, is examined using both individual events and composite day averages. We demonstrate that …

Internal Bore Seasonality And Tidal Pumping Of Subthermocline Waters At The Head Of The Monterey Submarine Canyon, Ryan K. Walter, P. Joe Phelan

Physics

This study utilizes more than a year of observations made in shallow waters (~30 m) at the head of the Monterey Submarine Canyon to assess variability in the physical environment and internal bore field. The interaction of the internal tide with the canyon rim results in a semidiurnal tidal period pumping of cold–water masses (subthermocline waters) onto the adjacent shelf (i.e., internal bores). These internal bores are shown to be significantly coherent with the local sea surface height with minimal spatial variability when comparing two sites near the canyon head region. During the summer months, and periods of strong regional …

Probing The Fitting Accuracy Of Active Galaxy Spectra, Aaron T. Line

Physics

Prior to this study, Dr. Vardha N. Bennert and collaborators selected a sample of ~100 local active galaxies to study the relationships between black hole mass and host galaxy properties. The broad Hβ width is necessary to determine black hole mass. This value is determined using a spectral decomposition code was scripted in IDL by Dr. Daeseong Park. The script fit spectral features and collected data for properties such as width of emission lines and continuum contribution percentages. The results were logged for further analysis.

To probe the accuracy of the fitting process, artificial spectra were created and fitted to …

Structure–Function Relationships Of Fullerene Esters In Polymer Solar Cells: Unexpected Structural Effects On Lifetime And Efficiency, Michael Tro, Alexis Sarabia, Kyle J. Bandaccari, David Oparko, Emma Lewis, Maxwell J. Giammona, Justin Isaac, Parisa Tajalli-Tehrani Valverde, Grace E. Chesmore, Thorsteinn Adalsteinsson, Richard P. Barber Jr., Brian J. Mcnelis

Physics

We report both transport measurements and spectroscopic data of polymer/fullerene blend photovoltaics using a small library of fullerene esters to correlate device properties with a range of functionality and structural diversity of the ester substituent. We observe that minor structural changes can lead to significant and surprising differences in device efficiency and lifetime. For example we have found that isomeric R-groups in the fullerene ester-based devices we have studied have dramatically different efficiencies. The characteristic lifetimes derived from both transport and spectroscopic measurements are generally comparable; however, some more rapid effects in specific fullerene esters are not observed spectroscopically. It …

Imaging The Oblique Propagation Of Electrons In Germanium Crystals At Low Temperature And Low Electric Field, R. A. Moffatt, Blas Cabrera, B. M. Corcoran, J. M. Kreikebaum, P. Redl, B. Shank, J. J. Yen, Betty A. Young, P. L. Brink, M. Cherry, A. Tomada, A. Phipps, B. Sadoulet, K. M. Sundqvist

Physics

Excited electrons in the conduction band of germanium collect into four energy minima, or valleys, in momentum space. These local minima have highly anisotropic mass tensors which cause the electrons to travel in directions which are oblique to an applied electric field at sub-Kelvin temperatures and low electric fields, in contrast to the more isotropic behavior of the holes. This experiment produces a full two-dimensional image of the oblique electron and hole propagation and the quantum transitions of electrons between valleys for electric fields oriented along the [0,0,1] direction. Charge carriers are excited with a focused laser pulse on one …

Parsec-Scale Structure And Kinematics Of Faint Tev Hbls, B. Glenn Piner, Philip G. Edwards

Physics

We present new multi-epoch Very Long Baseline Array (VLBA) observations of a set of TeV blazars drawn from our VLBA program to monitor all TeV-detected high-frequency peaked BL Lac objects (HBLs) at parsec scales. Most of these sources are faint in the radio, so they have not been well observed with VLBI by other surveys. Our previous measurements of apparent jet speeds in TeV HBLs showed apparent jet speeds that were subluminal or barely superluminal, suggesting jets with velocity structures at the parsec-scale. Here we present apparent jet speed measurements for eight new TeV HBLs, which for the first time …

The Giant Radio Array For Neutrino Detection, Jordan C. Hanson, Olivier Martineau-Huynh, Kumiko Kotera, Mauricio Bustamente, Didier Charrier, Sijbrand De Jong, Krijn D. De Vries, Ke Fang, Zhaoyang Feng, Chad Finley, Quanbu Gou, Junhua Gu, Hongbo Hu, Kohta Murase, Valentin Niess, Foteini Oikonomou, Nicolas Renault-Tinacci, Julia Schmid, Charles Timmermans, Zhen Wang, Xiangping Wu, Jianli Zhang, Yi Zhang

Physics

High-energy neutrino astronomy will probe the working of the most violent phenomena in the Universe. The Giant Radio Array for Neutrino Detection (GRAND) project consists of an array of ∼ 10⁵ radio antennas deployed over ∼ 200 000 km² in a mountainous site. It aims at detecting high-energy neutrinos via the measurement of air showers induced by the decay in the atmosphere of τ leptons produced by the interaction of cosmic neutrinos under the Earth surface. Our objective with GRAND is to reach a neutrino sensitivity of 5 × 10⁻¹¹E⁻² GeV⁻¹ cm⁻² s …