Astrophysics and Astronomy Commons^™

Improved Bounds On Lorentz Symmetry Violation From High-Energy Astrophysical Sources, Brett David Altschul

Faculty Publications

Observations of the synchrotron and inverse Compton emissions from ultrarelativistic electrons in astrophysical sources can reveal a great deal about the energy–momentum relations of those electrons. They can thus be used to place bounds on the possibility of Lorentz violation in the electron sector. Recent 𝛾 -ray telescope data allow the Lorentz-violating electron 𝑐^𝜈𝜇 parameters to be constrained extremely well, so that all bounds are at the level of 7×10⁻¹⁶ or better.

A Search For New Physics In B(S) To Mu+Mu- Decays Using Multivariate Data Analysis, And Development Of Particle Detection Technology With Silicon Pixel Detectors, Aidan Grummer

Physics & Astronomy ETDs

A suite of linked research projects is undertaken, combining a search for phenomena beyond the Standard Model of particle physics, development of new instruments for greater precision in detecting fundamental particles, and tracking and understanding the effect upon the detectors of the radiation that is an indelible element of their operating environment. Data recorded by the ATLAS Detector at CERN are employed in a search for evidence of undiscovered particles contributing to the rate of decays of B⁰ and B⁰_s mesons to dimuon final states. New applications of machine learning techniques are implemented to separate this signal …

How Much Has The Sun Influenced Northern Hemisphere Temperature Trends? An Ongoing Debate, Ronan Connolly, Willie Soon, Michael Connolly, Sallie Baliunas, Johan Berglund, C. John Butler, Rodolfo Gustavo Cionco, Ana G. Elias, Valery M. Fedorov, Hermann Harde, Gregory W. Henry, Douglas V. Hoyt, Ole Humlum, David R. Legates, Sebastian Lüning, Nicola Scafetta, Jan-Erik Solheim, László Szarka, Harry Van Loon, Víctor M. Velasco Herrera, Richard C. Willson, Hong Yan, Weijia Zhang

Information Systems and Engineering Management Research Publications

In order to evaluate how much Total Solar Irradiance (TSI) has influenced Northern Hemisphere surface air temperature trends, it is important to have reliable estimates of both quantities. Sixteen different estimates of the changes in TSI since at least the 19th century were compiled from the literature. Half of these estimates are "low variability" and half are "high variability". Meanwhile, five largely-independent methods for estimating Northern Hemisphere temperature trends were evaluated using: 1) only rural weather stations; 2) all available stations whether urban or rural (the standard approach); 3) only sea surface temperatures; 4) tree-ring widths as temperature proxies; 5) …

Measurements Of The Branching Fractions Of Λc+ →Pη And Λc+ →Pπ0 Decays At Belle, S. X. Li, C. P. Shen, I. Adachi, J. K. Ahn, H. Aihara, D. M. Asner, T. Aushev, R. Ayad, V. Babu, S. Bahinipati, P. Behera, J. Bennett, F. Bernlochner, M. Bessner, V. Bhardwaj, B. Bhuyan, T. Bilka, J. Biswal, A. Bobrov

Faculty and Student Publications

We report measurements of the branching fractions of singly Cabibbo-suppressed decays Λc+→pη and Λc+→pπ0 using the full Belle data sample corresponding to an integrated luminosity of 980.6 fb-1. The data were collected by the Belle detector at the KEKB e+e- asymmetric energy collider. A clear Λc+ signal is seen in the invariant mass distribution of pη. The fitted number of signal events of the Λc+→pη process is 7734±263; from this, we measure the ratio of branching fractions B(Λc+→pη)/B(Λc+→pK-π+)=[2.258±0.077(stat)±0.122(syst)]×10-2, from which we infer the branching fraction B(Λc+→pη)=[1.42±0.05(stat)±0.11(syst)]×10-3. In addition, no significant signal for Λc+→pπ0 is found, so an upper limit on …

Pinta: The Ugmrt Data Processing Pipeline For The Indian Pulsar Timing Array, Abhimanyu Susobhanan, Yogesh Maan, Bhal Chandra Joshi, T. Prabu, Shantanu Desai, K. Nobleson, Sai Chaitanya Susarla, Raghav Girgaonkar, Lankeswar Dey, Suryarao Bethapudi

Physics & Astronomy Faculty Publications

We introduce pinta, a pipeline for reducing the upgraded Giant Metre-wave Radio Telescope (uGMRT) raw pulsar timing data, developed for the Indian Pulsar Timing Array experiment. We provide a detailed description of the workflow and usage of pinta, as well as its computational performance and RFI mitigation characteristics. We also discuss a novel and independent determination of the relative time offsets between the different back-end modes of uGMRT and the interpretation of the uGMRT observation frequency settings and their agreement with results obtained from engineering tests. Further, we demonstrate the capability of pinta to generate data products which can produce …

Machine Learning Approach To Pattern Recognition In Nuclear Dynamics From The Ab Initio Symmetry-Adapted No-Core Shell Model, Oleksandr Molchanov

Honors Capstones

No abstract provided.

Probing The Galactic Agb Population Through Infrared And Sio Maser Emission, Megan O. Lewis

Physics & Astronomy ETDs

Stars on the Asymptotic Giant Branch (AGB) are of low to intermediate mass and have reached the end stages of stellar evolution. The mass-loss that stars undergo at this phase enshrouds the central star in a circumstellar envelope (CSE) that redistributes most of the stellar light into the infrared (IR) regime of the spectrum. In the CSEs of oxygen-rich AGB stars molecules including SiO form, and under certain conditions maser emission from SiO can make AGB stars bright beacons at radio frequencies (e.g., 43 and 86 GHz). SiO masers are ideal observational probes of AGB sources, providing data on their …

Pint: A Modern Software Package For Pulsar Timing, Jing Luo, S. M. Ransom, Paul B. Demorest, P. S. Ray, Anne M. Archibald, M. Kerr, Ross J. Jennings, Matteo Bachetti, Rutger Van Haasteren, Fredrick A. Jenet

Physics & Astronomy Faculty Publications

Over the past few decades, the measurement precision of some pulsar timing experiments has advanced from ~10 μs to ~10 ns, revealing many subtle phenomena. Such high precision demands both careful data handling and sophisticated timing models to avoid systematic error. To achieve these goals, we present PINT (PINT Is Not Tempo3), a high-precision Python pulsar timing data analysis package, which is hosted on GitHub and available on the Python Package Index (PyPI) as pint-pulsar. PINT is well tested, validated, object oriented, and modular, enabling interactive data analysis and providing an extensible and flexible development platform for timing applications. …

Gamma Rays From Massive Star Clusters G25 & G27, Abagael Barba, John W. Hewitt

Showcase of Osprey Advancements in Research and Scholarship (SOARS)

Project of Merit Winner

Cosmic rays have baffled astronomers for over a century, as all potential origins have yet to be determined. Most of these galactic accelerated atomic nuclei are thought to be created in two possible fashions: from a supernova, or within a massive star cluster (MSC). In this study, we analyzed gamma-ray emission coincident with two MSCs named G25 and G27. Using NASA’s Fermi Large Area Telescope (LAT), we confirmed that the sources of gamma rays are spatially extended and emit up to the maximum energies observed by the LAT. So far, only the closest MSC to Earth …

Monitoring The Night Sky For Iceact, Andre Sierra Alderete, John W. Hewitt, Warren Huelsnitz

Showcase of Osprey Advancements in Research and Scholarship (SOARS)

The neutral subatomic neutrinos are astronomical messengers that can provide us information to investigate the most violent astrophysical sources: supernovas, gamma-ray bursts, and cataclysmic phenomena involving black holes and neutron stars. As these astrophysical neutrinos freely travel from their point of origin without being scattered by interstellar magnetic fields, we can analyze these particles by observing cosmic-ray air showers on the Earth’s atmosphere. These are produced by the energetic neutrinos by interacting with the air particles that produce a wavefront of Cherenkov radiation. To better identify these background neutrinos, IceCube, the South Pole Neutrino Observatory, constructed an imaging air Cherenkov …

Gorgonians Are Foundation Species On Sponge-Dominated Mesophotic Coral Reefs In The Caribbean, Marc Slattery, Michael P. Lesser

Faculty and Student Publications

Foundation species (FS) regulate ecological processes within communities often facilitating biodiversity and habitat complexity. Typically FS are dominant structure-forming taxa; but less dominant taxa having disproportionate ecological impacts to the community can also be FS. Mesophotic coral ecosystems (MCEs) are deep coral reef (∼30–150 m) communities, often dominated by emergent sponges in the Caribbean Basin. Despite the potential competitive advantage of sponges on MCEs, gorgonians are also common constituents of these reefs. Data from the Bahamas demonstrate increased biodiversity and densities of sponges on mesophotic reefs with gorgonians relative to reefs without these species. Drawing upon fifteen years of field …

The Role Of Hydrated Minerals And Space Weathering Products In The Bluing Of Carbonaceous Asteroids, David Trang, Michelle S. Thompson, Bet E. Clark, Hannah H. Kaplan, Xiao-Duan Zou, Jian-Yang Li, Salvatore M. Ferrone, Victoria E. Hamilton, Amy A. Simon, Dennis C. Reuter, Lindsay P. Keller, M. Antonietta Barucci, Humberto Campins, Cateline Lantz, Daniella N. Dellagiustina, Ronald-Louis Ballouz, Erica R. Jawin, Harold Connolly Jr., Kevin J. Walsh, Dante Lauretta

School of Earth & Environment Departmental Research

The surfaces of airless bodies such as lunar and S-type asteroids typically become spectrally redder in visible to near-infrared reflectance with longer exposures to space weathering. However, some carbonaceous asteroids instead become spectrally bluer. Space weathering experiments on carbonaceous meteorites have provided some clues as to the space weathering products that could produce spectral bluing. We applied these experimental results to our Hapke radiative transfer model, with which we modeled spectral data from the OSIRIS-REx mission in order to determine whether these space weathering products—specifically, nanophase and microphase metallic iron, troilite, and magnetite—could explain the globally blue spectrum of the …

Search For The Dark Photon In B 0 → A′A′, A′ → E + E −, Μ + Μ −, And Π + Π − Decays At Belle, S. H. Park, Y. J. Kwon, I. Adachi, H. Aihara, S. Al Said, D. M. Asner, H. Atmacan, T. Aushev, R. Ayad, V. Babu, P. Behera, J. Bennett, M. Bessner, V. Bhardwaj, B. Bhuyan, T. Bilka, J. Biswal, G. Bonvicini, A. Bozek

Faculty and Student Publications

We present a search for the dark photon A′ in the B0 → A′A′ decays, where A′ subsequently decays to e+e−, μ+μ−, and π+π−. The search is performed by analyzing 772 × 106BB¯ events collected by the Belle detector at the KEKB e+e− energy-asymmetric collider at the ϒ(4S) resonance. No signal is found in the dark photon mass range 0.01 GeV/c2 ≤ mA′ ≤ 2.62 GeV/c2, and we set upper limits of the branching fraction of B0 → A′A′ at the 90% confidence level. The products of branching fractions, ℬ(B0→A′A′)×ℬ(A′→e+e−)2 and ℬ(B0→A′A′)×ℬ(A′→μ+μ−)2, have limits of the order of 10−8 depending …

Ast 101: Introductory Astronomy, Cuny School Of Professional Studies

Open Educational Resources

An exploration of our solar system’s creation and the planets in our solar system using the latest scientific information, recent probe data, and new discoveries in the science of extra-solar planetary astronomy. This course is based in part upon materials developed by the American Museum of Natural History and is used with permission by the School of Professional Studies for this course.

Tic 168789840: A Sextuply Eclipsing Sextuple Star System, B. P. Powell, V. B. Kostov, S. A. Rappaport, T. Borkovits, P. Zasche, A. Tokovinin, E. Kruse, D. W. Latham, B. T. Montet, Eric L.N. Jensen, R. Jayaraman, K. A. Collins, M. Mašek, C. Hellier, P. Evans, T.-G. Tan, J. E. Schlieder, G. Torres, A. P. Smale, A. H. Friedman, T. Barclay, R. Gagliano, E. V. Quintana, T. L. Jacobs, E. A. Gilbert, M. H. Kristiansen, K. D. Colón, D. M. Lacourse, G. Olmschenk, M. Omohundro, J. D. Schnittman, H. M. Schwengeler, R. K. Barry, I. A. Terentev, P. Boyd, A. R. Schmitt, S. M. Quinn, A. Vanderburg, E. Palle, J. Armstrong, G. R. Ricker, R. Vanderspek, S. Seager, J. N. Winn, J. M. Jenkins, D. A. Caldwell, B. Wohler, B. Shiao, C. J. Burke, T. Daylan, J. Villaseñor

Physics & Astronomy Faculty Works

We report the discovery of a sextuply eclipsing sextuple star system from TESS data, TIC 168789840, also known as TYC 7037-89-1, the first known sextuple system consisting of three eclipsing binaries. The target was observed in Sectors 4 and 5 during Cycle 1, with lightcurves extracted from TESS Full Frame Image data. It was also previously observed by the WASP survey and ASAS-SN. The system consists of three gravitationally bound eclipsing binaries in a hierarchical structure of an inner quadruple system with an outer binary subsystem. Follow-up observations from several different observatories were conducted as a means of determining additional …

Tess Delivers Five New Hot Giant Planets Orbiting Bright Stars From The Full-Frame Images, J. E. Rodriguez, S. N. Quinn, G. Zhou, A. Vanderburg, L. D. Nielsen, R. A. Wittenmyer, R. Brahm, P. A. Reed, C. X. Huang, S. Vach, D. R. Ciardi, R. J. Oelkers, K. G. Stassun, C. Hellier, B. S. Gaudi, J. D. Eastman, K. A. Collins, A. Bieryla, S. Christian, D. W. Latham, I. Carleo, D. J. Wright, E. Matthews, E. J. Gonzales, C. Ziegler, C. D. Dressing, S. B. Howell, T.-G. Tan, J. Wittrock, P. Plavchan, K. K. Mcleod, D. Baker, G. Wang, D. J. Radford, R. P. Schwarz, M. Esposito, G. R. Ricker, R. K. Vanderspek, S. Seager, J. N. Winn, J. M. Jenkins, B. Addison, D. R. Anderosn, T. Barclay, T. G. Beatty, P. Berlind, F. Bouchy, M. Bowen, B. P. Bowler, C. E. Brasseur, C. Briceño, D. A. Caldwell, M. L. Calkins, S. Cartwright, P. Chaturvedi, G. Chaverot, S. Chimaladinne, J. L. Christiansen, K. I. Collins, I. J. M. Crossfield, K. Eastridge, N. Espinoza, G. A. Esquerdo, D. L. Felix, T. Fenske, W. Fong, T. Gan, S. Giacalone, H. Gill, L. Gordon, A. Granados, N. Grieves, E. W. Guenther, N. Guerrero, T. Henning, C. E. Henze, K. Hesse, M. J. Hobson, J. Horner, D. J. James, Eric L. N. Jensen, M. Jimenez, A. Jordán, S. R. Kane, J. Kielkopf, K. Kim, R. B. Kuhn, N. Latouf, N. M. Law, A. M. Levine, M. B. Lund, A. W. Mann, S. Mao, R. A. Matson, M. W. Mengel, J. Mink, P. Newman, T. O’Dwyer, J. Okumura, E. Palle, J. Pepper, E. V. Quintana, P. Sarkis, A. B. Savel, J. E. Schlieder, C. Schnaible, A. Shporer, R. Sefako, J. V. Seidel, R. J. Siverd, B. Skinner, M. Stalport, D. J. Stevens, C. Stibbards, C. G. Tinney, R. G. West, D. A. Yahalomi, H. Zhang

Physics & Astronomy Faculty Works

We present the discovery and characterization of five hot and warm Jupiters—TOI-628 b (TIC 281408474; HD 288842), TOI-640 b (TIC 147977348), TOI-1333 b (TIC 395171208, BD+47 3521A), TOI-1478 b (TIC 409794137), and TOI-1601 b (TIC 139375960)—based on data from NASA's Transiting Exoplanet Survey Satellite (TESS). The five planets were identified from the full-frame images and were confirmed through a series of photometric and spectroscopic follow-up observations by the TESS Follow-up Observing Program Working Group. The planets are all Jovian size (RP = 1.01–1.77 RJ) and have masses that range from 0.85 to 6.33 MJ. The host stars of these systems …

A Hot Mini-Neptune In The Radius Valley Orbiting Solar Analogue Hd 110113, H. P. Osborn, D. J. Armstrong, V. Adibekyan, K. A. Collins, E. Delgado-Mena, S. B. Howell, C. Hellier, G. W. King, J. Lillo-Box, L. D. Nielsen, J. F. Otegi, N. C. Santos, C. Ziegler, D. R. Anderson, C. Briceño, C. Burke, D. Bayliss, D. Barrado, E. M. Bryant, D. J. A. Brown, S. C. C. Barros, F. Bouchy, D. A. Caldwell, D. M. Conti, R. F. Díaz, D. Dragomir, M. Deleuil, O. D. S. Demangeon, C. Dorn, T. Daylan, P. Figueira, R. Helled, S. Hoyer, J. M. Jenkins, Eric L.N. Jensen, D. W. Latham, N. Law, D. R. Louie, A. W. Mann, A. Osborn, D. L. Pollacco, D. R. Rodriguez, B. V. Rackham, G. Ricker, N. J. Scott, S. G. Sousa, S. Seager, K. G. Stassun, J. C. Smith, P. Strøm, S. Udry, J. Villaseñor, R. Vanderspek, R. West, P. J. Wheatley, J. N. Winn

Physics & Astronomy Faculty Works

We report the discovery of HD 110113 b (TESS object of interest-755.01), a transiting mini-Neptune exoplanet on a 2.5-d orbit around the solar-analogue HD 110113 (Teff = 5730 K). Using TESS photometry and High Accuracy Radial velocity Planet Searcher (HARPS) radial velocities gathered by the NCORES program, we find that HD 110113 b has a radius of 2.05 ± 0.12  R⊕ and a mass of 4.55 ± 0.62  M⊕. The resulting density of 2.90+0.75−0.59  g cm−3 is significantly lower than would be expected from a pure-rock world; therefore HD 110113 b must be a mini-Neptune with a significant volatile atmosphere. …

Distances To Galactic X-Ray Binaries With Gaia Dr2, R. M. Arnason, H. Papei, P. Barmby, A. Bahramian, M. D. Gorski

Physics and Astronomy Publications

Precise and accurate measurements of distances to Galactic X-ray binaries (XRBs) reduce uncertainties in the determination of XRB physical parameters. We have cross-matched the XRB catalogues of Liu, van Paradijs & van den Heuvel to the results of Gaia Data Release 2. We identify 86 XRBs with a Gaia candidate counterpart, of which 32 are low-mass X-ray binaries (LMXBs) and 54 are high-mass X-ray binaries (HMXBs). Distances to Gaia candidate counterparts are, on average, consistent with those measured by Hipparcos and radio parallaxes. When compared to distances measured by Gaia candidate counterparts, distances measured using Type I X-ray bursts are …

On The Observational Difference Between The Accretion Disk-Corona Connections Among Super- And Sub-Eddington Accreting Active Galactic Nuclei, Hezhen Liu, B. Luo, W. N. Brandt, Michael S. Brotherton, Sarah C. Gallagher, Q. Ni, Ohad Shemmer, J. D. Timlin

Physics and Astronomy Publications

We present a systematic X-ray and multiwavelength study of a sample of 47 active galactic nuclei (AGNs) with reverberation mapping measurements. This sample includes 21 super-Eddington accreting AGNs and 26 sub-Eddington accreting AGNs. Using high-state observations with simultaneous X-ray and UV/optical measurements, we investigate whether super-Eddington accreting AGNs exhibit different accretion disk-corona connections compared to sub-Eddington accreting AGNs. We find tight correlations between the X-ray-to-UV/optical spectral slope parameter (α OX) and the monochromatic luminosity at 2500 Å (L 2500Å) for both the super- and sub-Eddington subsamples. The best-fit α OX-L 2500Å relations are consistent overall, indicating that super-Eddington accreting AGNs …

Precise Transit And Radial-Velocity Characterization Of A Resonant Pair: The Warm Jupiter Toi-216c And Eccentric Warm Neptune Toi-216b, R. I. Dawson, C. X. Huang, R. Brahm, K. A. Collins, M. J. Hobson, A. Jordán, J. Dong, J. Korth, T. Trifonov, L. Abe, A. Agabi, I. Bruni, R. P. Butler, M. Barbieri, K. I. Collins, D. M. Conti, J. D. Crane, N. Crouzet, G. Dransfield, P. Evans, N. Espinoza, T. Gan, T. Guillot, T. Henning, J. J. Lissauer, Eric L. N. Jensen, W. M. Sainte, D. Mékarnia, G. Myers, S. Nandakumar, H. M. Relles, P. Sarkis, P. Torres, S. Shectman, F.-X. Schmider, A. Shporer, C. Stockdale, J. Teske, A. H. M. J. Triaud, S. X. Wang, C. Ziegler, G. Ricker, R. Vanderspek, D. W. Latham, S. Seager, J. Winn, J. M. Jenkins, L. G. Bouma, J. A. Burt, D. Charbonneau, A. M. Levine, S. Mcdermott, B. Mclean, M. E. Rose, A. Vanderburg, B. Wohler

Physics & Astronomy Faculty Works

TOI-216 hosts a pair of warm, large exoplanets discovered by the TESS mission. These planets were found to be in or near the 2:1 resonance, and both of them exhibit transit timing variations (TTVs). Precise characterization of the planets' masses and radii, orbital properties, and resonant behavior can test theories for the origins of planets orbiting close to their stars. Previous characterization of the system using the first six sectors of TESS data suffered from a degeneracy between planet mass and orbital eccentricity. Radial-velocity measurements using HARPS, FEROS, and the Planet Finder Spectrograph break that degeneracy, and an expanded TTV …

A New Method For Estimating The Physical Characteristics Of Martian Dust Devils, Shelly Cahoon Mann

Mechanical & Aerospace Engineering Theses & Dissertations

Critical to the future exploration of Mars is having a detailed understanding of the atmospheric environment and its potential dangers. The dust devil is one of these potential dangers. The transport of dust through saltation is believed to be the driving mechanism responsible for Martian weather patterns. The two primary mechanisms for dust transport are dust storms and dust devils. Dust devils on Mars are a frequent occurrence with one in five so called giant dust devils being large enough to leave scars on the surface that are visible from space. Due to the thin atmosphere, winds of 60 mph …

R Coronae Borealis Star Evolution: Simulating 3d Merger Events To 1d Stellar Evolution Including Large-Scale Nucleosynthesis, Bradley Munson, Emmanouil Chatzopoulos, Juhan Frank, Geoffrey Clayton, Courtney Crawford, Pavel A. Denissenkov, Falk Herwig

Faculty Publications

R Coronae Borealis (RCB) stars are rare hydrogen-deficient carbon-rich variable supergiants thought to be the result of dynamically unstable white dwarf mergers. We attempt to model RCB stars through all the relevant timescales by simulating a merger event in Octo-tiger, a 3D adaptive mesh refinement (AMR) hydrodynamics code, and mapping the post-merger object into MESA, a 1D stellar evolution code. We then post-process the nucleosynthesis on a much larger nuclear reaction network to study the enhancement of s-process elements. We present models that match observations or previous studies in most surface abundances, isotopic ratios, early evolution, and lifetimes. We also …

Human-Assisted Sample Return Mission At The Schrödinger Basin, Lunar Far Side, Using A New Geologic Map And Rover Traverses, E. C. Czaplinski, E. M. Harrington, S. K. Bell, G. D. Tolometti, B. E. Furrant, V. T. Bickel, C. I. Honniball, S. N. Martinez, A. Rogaski, H. M. Sargeant, D. A. Kring

Space and Planetary Science Faculty Publications and Presentations

The Schrodinger basin on the south polar lunar far side has been highlighted as a promising target for future exploration. This report provides a high-resolution geologic map in the southwest peak-ring (SWPR) area of the Schrodinger basin, emphasizing structural features and detailed mapping of exposed outcrops within the peak ring. Outcrops are correlated with mineralogical data from the Moon Mineralogical Mapper instrument. Geologic mapping reveals a complex structural history within the basin through a system of radially oriented faults. Further, the geologic map shows both faulted and magmatic contacts between peak-ring mineralogies, providing both structural and magmatic context for understanding …

Comparing Dust In Other Galaxies To Dust In Our Galaxy, Fatima Elkhatib

Senior Theses

Interstellar dust in galaxies has a profound effect on the galaxies’ light output and apparent properties as well as on the physical processes connected to star formation. Therefore, to understand the true properties of the galaxies around us, it is important to understand the dust in those galaxies and compare it to the dust in our galaxy. To do this, we study the effects of dust on background quasars by analyzing interstellar reddening and extinction. It has been shown that many quasars look redder and dimmer than the average quasar when observing them from Earth, due to the dust in …

Gwtc-2: Compact Binary Coalescences Observed By Ligo And Virgo During The First Half Of The Third Observing Run, Ligo Scientific Collaboration, Virgo Collaboration, Tiffany Z. Summerscales

Faculty Publications

We report on gravitational-wave discoveries from compact binary coalescences detected by Advanced LIGO and Advanced Virgo in the first half of the third observing run (O3a) between 1 April 2019 15∶00 UTC and 1 October 2019 15∶00 UTC. By imposing a false-alarm-rate threshold of two per year in each of the four search pipelines that constitute our search, we present 39 candidate gravitational-wave events. At this threshold, we expect a contamination fraction of less than 10%. Of these, 26 candidate events were reported previously in near-real time through gamma-ray coordinates network notices and circulars; 13 are reported here for the …

Galaxy And Mass Assembly (Gama): The Inferred Mass–Metallicity Relation From Z = 0 To 3.5 Via Forensic Sed Fitting, Sabine Bellstedt, Aaron S G Robotham, Simon P. Driver, Jessica E. Thorne, Luke J M Davies, Benne Holwerda, Andrew M. Hopkins, Maritza A. Lara-Lopez, Ángel R. López-Sánchez, Steven Phillipps

Faculty and Staff Scholarship

We analyse the metallicity histories of ∼4500 galaxies from the GAMA survey at z < 0.06 modelled by the SED-fitting code PROSPECT using an evolving metallicity implementation. These metallicity histories, in combination with the associated star formation histories, allow us to analyse the inferred gas-phase mass–metallicity relation. Furthermore, we extract the mass– metallicity relation at a sequence of epochs in cosmic history, to track the evolving mass–metallicity relation with time. Through comparison with observations of gas-phase metallicity over a large range of redshifts, we show that, remarkably, our forensic SED analysis has produced an evolving mass–metallicity relationship that is consistent with observations at all epochs. We additionally analyse the three-dimensional mass–metallicity–SFR space, showing that galaxies occupy a clearly defined plane. This plane is shown to be subtly evolving, displaying an increased tilt with time caused by general enrichment, and also the slowing down of star formation with cosmic time. This evolution is most apparent at lookback times greater than 7 Gyr. The trends in metallicity recovered in this work highlight that the evolving metallicity implementation used within the SED-fitting code PROSPECT produces reasonable metallicity results over the history of a galaxy. This is expected to provide a significant improvement to the accuracy of the SED-fitting outputs.

Determining The Origins Of Helix Glitches In Ligo’S H1 Detector, Kara Shepard

Honors Scholars & Undergraduate Research Poster Symposium Programs

The LIGO detectors are ultra-sensitive, making them susceptible to glitches from the noise that can block gravitational wave signals. In order to reduce the number of glitches that occur in the detector, the cause of the glitches must be found. I am researching the Helix glitch to try and determine its origin. This is accomplished by studying the times at which the glitch occurred in the detector and then looking for factors that may have caused a glitch to happen around the same time, to see if there are any correlations.

Light And Truth: Measuring Unseen Harm In Individuals And Communities, Hannah Pfost

Undergraduate Honors Theses

While the fields of physics and international development may seem disparate, the insights gained from studying each one of them can improve understanding of the other. Here, I demonstrate that concept as applied to computational optics and historical memory. Thus, the purpose of this project is threefold: (1) to computationally model light transport through tissue, and use that model to inform choices about a physical system; (2) to determine the types of historical memory recommended in the final reports of truth commissions; and (3) to give evidence for the usefulness of human-centered design in both areas. To model light transport, …

Primordial Power Spectrum From A Matter-Ekpyrotic Bounce Scenario In Loop Quantum Cosmology, Bao-Fei Li, Sahil Saini, Parampreet Singh

Faculty Publications

A union of matter bounce and ekpyrotic scenarios is often studied in an attempt to combine the most promising features of these two models. Since nonperturbative quantum geometric effects in loop quantum cosmology (LQC) result in natural bouncing scenarios without any violation of energy conditions or fine tuning, an investigation of matter-ekpyrotic bounce scenario is interesting to explore in this quantum gravitational setting. In this work, we explore this unified phenomenological model for a spatially flat Friedmann-Lemaistre-Robertson-Walker (FLRW) universe in LQC filled with dust and a scalar field in an ekpyrotic scenario like negative potential. Background dynamics and the power …

Mass-Velocity Dispersion Relation In Hiflugcs Galaxy Clusters, Pengfei Li, Stacy S. Mcgaugh

Faculty Scholarship

We investigate the mass-velocity dispersion relation (MVDR) in 29 galaxy clusters in the HIghest X-ray FLUx Galaxy Cluster Sample (HIFLUGCS). We measure the spatially resolved, line-of-sight velocity dispersion profiles of these clusters, which we find to be mostly flat at large radii, reminiscent of the rotation curves of galaxies. We discover a tight empirical relation between the baryonic mass M bar and the flat velocity dispersion σ of the member galaxies, i.e., MVDR,, with the lognormal intrinsic scatter of 12 -3 +3. The residuals of the MVDR are uncorrelated with other cluster properties like temperature, cluster radius, baryonic mass surface …