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Characterizing Cool Brown Dwarfs And Low-Mass Companions With Low-Resolution Near-Infrared Spectra, Paige Godfrey 2017 The Graduate Center, City University of New York

Characterizing Cool Brown Dwarfs And Low-Mass Companions With Low-Resolution Near-Infrared Spectra, Paige Godfrey

All Graduate Works by Year: Dissertations, Theses, and Capstone Projects

Exoplanet direct detections are reaching the temperature regime of cool brown dwarfs, motivating further understanding of the coolest substellar atmospheres. These objects, T and Y dwarfs, are numerous and isolated in the field, thus making them easier to study in detail than objects in companion systems. Brown dwarf spectral types are derived from spectral morphology and generally appear to correspond with decreasing mass and effective temperature (Teff). However, spectral subclasses of the colder objects do not share this monotonic temperature correlation, indicating that secondary parameters (gravity, metallicity, dust) significantly influence spectral morphology. These secondary atmospheric parameters can provide insight ...


Book Review: Shoot The Moon: A Complete Guide To Lunar Imaging, T. D. Oswalt 2017 Embry-Riddle Aeronautical University - Daytona Beach

Book Review: Shoot The Moon: A Complete Guide To Lunar Imaging, T. D. Oswalt

Publications

This document is Dr. Oswalt’s review of Shoot the Moon: a Complete Guide to Lunar Imaging by Dupont-Bloch, Nicolas. Cambridge, 2016, 323 p index, 9781107548442 $39.95, 9781316657867 $32.00.


The Sluggs Survey: Using Extended Stellar Kinematics To Disentangle The Formation Histories Of Low-Mass S0 Galaxies, Sabine Bellstedt, Duncan Forbes, Caroline Foster, Aaron Romanowsky, Jean Brodie, Nicola Pastorello, Adebusola Alabi, Alexa Villaume 2017 Swinburne University of Technology

The Sluggs Survey: Using Extended Stellar Kinematics To Disentangle The Formation Histories Of Low-Mass S0 Galaxies, Sabine Bellstedt, Duncan Forbes, Caroline Foster, Aaron Romanowsky, Jean Brodie, Nicola Pastorello, Adebusola Alabi, Alexa Villaume

Faculty Publications

We utilize the DEIMOS instrument on the Keck telescope to measure the wide-field stellar kinematics of early-type galaxies as part of the SAGES Legacy Unifying Globulars and GalaxieS (SLUGGS) survey. In this paper, we focus on some of the lowest stellar mass lenticular galaxies within this survey, namely NGC 2549, NGC 4474, NGC 4459 and NGC 7457, performing detailed kinematic analyses out to large radial distances of ∼2–3 effective radii. For NGC 2549, we present the first analysis of data taken with the SuperSKiMS (Stellar Kinematics from Multiple Slits) technique. To better probe kinematic variations in the outskirts of ...


Almost Dark Galaxies: The Search For Optical Counterparts, Quinton O. Singer 2017 Macalester College

Almost Dark Galaxies: The Search For Optical Counterparts, Quinton O. Singer

Macalester Journal of Physics and Astronomy

Presented in this paper are results from neutral hydrogen (HI) imaging and analysis of the "Almost Dark" galaxies AGC 219533, AGC 227982, and AGC 268363 using new, higher resolution observations from the Very Large Array (VLA). Selected from the ALFALFA survey, "Almost Dark" galaxies possess significant HI reservoirs but, when the HI data is compared to survey-depth ground-based optical imaging, their optical stellar counterparts have extremely low surface brightnesses. AGC 219533 is one such object. The other two sources, AGC 227982 and AGC 26833, were candidate dark galaxies, as no stellar counterpart was identified in initial ALFALFA optical matching, and ...


Intervalley Scattering Rates In Tellurium Observed Via Time-Resolved Terahertz Spectroscopy, Joshua R. Rollag 2017 Macalester College

Intervalley Scattering Rates In Tellurium Observed Via Time-Resolved Terahertz Spectroscopy, Joshua R. Rollag

Macalester Journal of Physics and Astronomy

We conducted time-resolved terahertz spectroscopy measurements on the elemental semiconductor tellurium. Pump-probe measurements were used to find the conductivity as a function of time in single crystalline tellurium samples. It was found that the excitation dynamics in tellurium changes for photon energies of 1.03 eV and 1.55 eV. The change in these excitation dynamics was attributed to intervalley scattering effects. A model using intervalley scattering and Auger recombination was fit to the data, giving a value of 2.28 ps for the intervalley scattering time constant in tellurium.


Transient Photoconductivity Of A Thermoelectric Nanomaterial Pedot:Pss With Tecu Nanowires, Gunnar J. Footh, Michaela S. Koller, James Heyman 2017 Macalester College

Transient Photoconductivity Of A Thermoelectric Nanomaterial Pedot:Pss With Tecu Nanowires, Gunnar J. Footh, Michaela S. Koller, James Heyman

Macalester Journal of Physics and Astronomy

Thermoelectric materials are able to transfer heat energy into electrical energy. They have many important applications, and an increased understanding of them would allow the scientific community to develop more efficient thermoelectrics. We provide here transient photoconductivity measurements of a thermoelectric nanomaterial - PEDOT:PSS with TeCu nanowires on quartz substrate. Increased copper concentration in nanowires decreases photoconductivity in both transmission and reflectance measurements. Fermi blocking provides a reasonable explanation for this decrease in photoconductivity, which occurs when total nanowire mass approaches ~15% copper concentration.


A Direct Comparison Of Lyman-Alpha And Neutral Hydrogen Morphologies, Kathleen Fitzgibbon, John M. Cannon 2017 Macalester College

A Direct Comparison Of Lyman-Alpha And Neutral Hydrogen Morphologies, Kathleen Fitzgibbon, John M. Cannon

Macalester Journal of Physics and Astronomy

The Lyman-Alpha Reference Sample (LARS) and its extension (eLARS) represent an exhaustive campaign to reverse-engineer galaxies. The main goal is to understand how \lya radiation is transported within galaxies: what fraction of it escapes, and what physical properties affect the \lya morphology and radiative transport (e.g., dust and gas content, metallicity, kinematics, properties of the producing and underlying stellar populations). Two galaxies from the sample, LARS02 and LARS09, were observed using the B and C configurations of the Very Large Array to examine the neutral hydrogen emission, which can be used to determine a galaxy's neutral hydrogen (HI ...


Literature Review: Biomimetic And Conventional Aircraft Wing Tips, Naseeb Ahmed Siddiqui, Waqar Asrar, Erwin Sulaeman 2017 International Islamic University - Malaysia

Literature Review: Biomimetic And Conventional Aircraft Wing Tips, Naseeb Ahmed Siddiqui, Waqar Asrar, Erwin Sulaeman

International Journal of Aviation, Aeronautics, and Aerospace

This paper is an attempt to summarize the effect of wing tip devices employed by birds, as well as aeronautical engineers in the past to improve the performance characteristics of aircraft. The focus is on reduction of the induced drag or drag due to lift also known as inviscid drag. This paper will provide an insight on both biomimetic and conventional wing tip approaches to reduce the induced drag. Prior analysis and experiments on the aerodynamics of airplane performance due to both these separate studies have been discussed. The needs of the industry and their past inventions have been described ...


Shape Modeling And Boulder Napping Of Asteroid 1992 Uy4., Nicholas D Duong 2017 University of Louisville

Shape Modeling And Boulder Napping Of Asteroid 1992 Uy4., Nicholas D Duong

College of Arts & Sciences Senior Honors Theses

In August 2005, the near-Earth Asteroid 1992 UY4 made a close flyby, coming within 0.04 au of our planet. Between the dates of 1-10 August 2005, it was observed via delay-Doppler radar imaging by the Arecibo Observatory (2380 MHz, 13 cm) and the DSS-14 antenna at the Goldstone Deep Space Communications Complex (8560 MHz, 3.5 cm). The images achieve a resolution as fine as 7.5 m/pixel and reveal a lumpy and modestly asymmetric object. The images also revealed the presence of numerous large boulders/blocks on the surface of 1992 UY4. By using the modeling software ...


Accuracy And Stability Of Integration Methods For Neutrino Transport In Core Collapse Supernovae, Kyle A. Gregory 2017 kgrego12

Accuracy And Stability Of Integration Methods For Neutrino Transport In Core Collapse Supernovae, Kyle A. Gregory

University of Tennessee Honors Thesis Projects

No abstract provided.


Detection And Characterization Of Extrasolar Planets Through Planet-Disk Dynamical Interactions, Maryam Tabeshian 2017 The University of Western Ontario

Detection And Characterization Of Extrasolar Planets Through Planet-Disk Dynamical Interactions, Maryam Tabeshian

Electronic Thesis and Dissertation Repository

Structures observed in circumstellar disks may be caused by gravitational interaction with planetary or stellar companions. These perturbed disks are often signposts of planet birth in exoplanetary systems, and offer insights into the properties of both the disk and the perturbing planets. Therefore, structures observed in these disks provide a powerful tool for detecting and studying extrasolar planetary systems. In this work, we examine the link between disk structures and nearby/embedded planets using numerical simulations of both hypothetical and observed disk systems.

We demonstrate that gaps can be opened in dynamically cold debris disks at the mean-motion resonances (MMRs ...


Fermi-Lat Daily Monitoring Observations Of The Microquasar Cygnus X-1, Austin P. Waldron, Stephen R. Hood, Arash Bodaghee 2017 Georgia College and State University

Fermi-Lat Daily Monitoring Observations Of The Microquasar Cygnus X-1, Austin P. Waldron, Stephen R. Hood, Arash Bodaghee

Georgia College Student Research Events

Detection of gamma-ray emission from microquasars is important for understanding particle acceleration in the jet, and for constraining leptonic/hadronic emission models. We present a continuation of a 1-d likelihood analysis on gamma-ray observations by Fermi-LAT (0.1-10 GeV) of the accreting black hole candidate Cygnus X-1. Combining this gamma-ray data with available X-ray monitoring data from Swift and MAXI allowed us to reveal over a dozen days (in 2008-2016) during which Cyg X-1 displayed low-significance (3-4 sigma) excesses, many of which were contemporaneous with apparent transitions in the X-rays.


Rice, Laban Lacy, 1870-1973 (Mss 605), Manuscripts & Folklife Archives 2017 Western Kentucky University

Rice, Laban Lacy, 1870-1973 (Mss 605), Manuscripts & Folklife Archives

MSS Finding Aids

Finding aid only for Manuscripts Collection 605. Correspondence, writings, hotographs, clippings, and papers of Laban Lacy Rice, a Webster, County, Kentucky native, educator, author, lecturer, poet, and president of Cumberland University, Lebanon, Tennessee. Includes his scientific writing, principally on astronomy, relativity and cosmology, as well as fiction, poetry, and autobiographical writing. Also includes some correspondence and papers relating to his brother, poet and dramatist Cale Young Rice, and sister-in-law, author Alice Hegan Rice.


Detection Of Supermassive Black Holes In Two Virgo Ultracompact Dwarf Galaxies, Christopher Ahn, Anil Seth, Mark den Brok, Jay Strader, Holger Baumgardt, Remco van den Bosch, Igor Chilingarian, Matthias Frank, Michael Hilker, Richard McDermid, Steffen Mieske, Aaron Romanowsky, Lee Spitler, Jean Brodie, Nadine Neumayer, Jonelle Walsh 2017 University of Utah

Detection Of Supermassive Black Holes In Two Virgo Ultracompact Dwarf Galaxies, Christopher Ahn, Anil Seth, Mark Den Brok, Jay Strader, Holger Baumgardt, Remco Van Den Bosch, Igor Chilingarian, Matthias Frank, Michael Hilker, Richard Mcdermid, Steffen Mieske, Aaron Romanowsky, Lee Spitler, Jean Brodie, Nadine Neumayer, Jonelle Walsh

Faculty Publications

No abstract provided.


Detection Of Supermassive Black Holes In Two Virgo Ultracompact Dwarf Galaxies, Christopher P. Ahn, Anil C. Seth, Mark den Brok, Jay Strader, Holger Baumgardt, Remco C.E. van den Bosch, Igor Chilingarian, Matthias J. Frank, Michael Hilker, Richard McDermid, Steffen Mieske, Aaron J. Romanowsky, Lee R. Spitler, Jean P. Brodie, Nadine Neumayer, Jonelle L. Walsh 2017 University of Utah

Detection Of Supermassive Black Holes In Two Virgo Ultracompact Dwarf Galaxies, Christopher P. Ahn, Anil C. Seth, Mark Den Brok, Jay Strader, Holger Baumgardt, Remco C.E. Van Den Bosch, Igor Chilingarian, Matthias J. Frank, Michael Hilker, Richard Mcdermid, Steffen Mieske, Aaron J. Romanowsky, Lee R. Spitler, Jean P. Brodie, Nadine Neumayer, Jonelle L. Walsh

Aaron J. Romanowsky

No abstract provided.


Magnetic Massive Stars As Progenitors Of ‘Heavy’ Stellar-Mass Black Holes, V. Petit, Z. Keszthelyi, R. MacInnis, David H. Cohen, R. H. D. Townsend, G. A. Wade, S. L. Thomas, S. P. Owocki, J. Puls, A. Ud-Doula 2017 Swarthmore College

Magnetic Massive Stars As Progenitors Of ‘Heavy’ Stellar-Mass Black Holes, V. Petit, Z. Keszthelyi, R. Macinnis, David H. Cohen, R. H. D. Townsend, G. A. Wade, S. L. Thomas, S. P. Owocki, J. Puls, A. Ud-Doula

Physics & Astronomy Faculty Works

The groundbreaking detection of gravitational waves produced by the inspiralling and coalescence of the black hole (BH) binary GW150914 confirms the existence of ‘heavy’ stellar-mass BHs with masses >25 M⊙. Initial characterization of the system by Abbott et al. supposes that the formation of BHs with such large masses from the evolution of single massive stars is only feasible if the wind mass-loss rates of the progenitors were greatly reduced relative to the mass-loss rates of massive stars in the Galaxy, concluding that heavy BHs must form in low-metallicity (Z ≲ 0.25-0.5 Z⊙) environments. However, strong surface magnetic fields ...


Diverse Stellar Haloes In Nearby Milky Way Mass Disc Galaxies., Benjamin Harmsen, Antonela Monachesi, Eric F. Bell, Roelof S. de Jong, Jeremy Bailin, David J. Radburn-Smith, Benne W. Holwerda 2017 University of Michigan-Ann Arbor

Diverse Stellar Haloes In Nearby Milky Way Mass Disc Galaxies., Benjamin Harmsen, Antonela Monachesi, Eric F. Bell, Roelof S. De Jong, Jeremy Bailin, David J. Radburn-Smith, Benne W. Holwerda

Faculty Scholarship

We have examined the resolved stellar populations at large galactocentric distances along the minor axis (from 10 kpc up to between 40 and 75 kpc), with limited major axis coverage, of six nearby highly inclined MilkyWay (MW) mass disc galaxies using Hubble Space Telescope data from the Galaxy haloes, Outer discs, Substructure, Thick discs, and Star clusters (GHOSTS) survey. We select red giant branch stars to derive stellar halo density profiles. The projected minor axis density profiles can be approximated by power laws with projected slopes of −2 to −3.7 and a diversity of stellar halo masses of 1 ...


Table Of Contents, 2017 University of South Carolina

Table Of Contents

Journal of the South Carolina Academy of Science

No abstract provided.


The Velocity Dispersion Function Of Very Massive Galaxy Clusters: Abell 2029 And Coma, Jubee Sohn, Margaret J. Geller, H. Jabran Zahid, Daniel G. Fabricant, Antonaldo Diaferio, Kenneth J. Rines 2017 Western Washington University

The Velocity Dispersion Function Of Very Massive Galaxy Clusters: Abell 2029 And Coma, Jubee Sohn, Margaret J. Geller, H. Jabran Zahid, Daniel G. Fabricant, Antonaldo Diaferio, Kenneth J. Rines

Physics & Astronomy

Based on an extensive redshift survey for galaxy clusters Abell 2029 and Coma, we measure the luminosity functions (LFs) and stellar mass functions (SMFs) for the entire cluster member galaxies. Most importantly, we measure the velocity dispersion functions (VDFs) for quiescent members. The MMT/Hectospec redshift survey for galaxies in A2029 identifies 982 spectroscopic members; for 838 members, we derive the central velocity dispersion from the spectroscopy. Coma is the only other cluster surveyed as densely. The LFs, SMFs, and VDFs for A2029 and Coma are essentially identical. The SMFs of the clusters are consistent with simulations. The A2029 and ...


Book Review: From The Realm Of The Nebulae To Populations Of Galaxies: Dialogues On A Century Of Research, Astrophysics And Space Science Library, 435, T. D. Oswalt 2017 Embry-Riddle Aeronautical University - Daytona Beach

Book Review: From The Realm Of The Nebulae To Populations Of Galaxies: Dialogues On A Century Of Research, Astrophysics And Space Science Library, 435, T. D. Oswalt

Publications

This document is Dr. Oswalt’s review of From the Realm of the Nebulae to Populations of Galaxies : Dialogues on a Century of Research, Astrophysics and Space Science Library, 435. by Mauro D'Onofrio, Roberto Rampazzo, and Simone Zaggia Springer, 2016 785p bibl index afp, 9783319310046 $279.00, 9783319310060 $219.00


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