The Sluggs Survey: Using Extended Stellar Kinematics To Disentangle The Formation Histories Of Low-Mass S0 Galaxies,
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 the …
Active Control Of Cylindrical Shells Using The Weighted Sum Of Spatial Gradients (Wssg) Control Metric,
2017
Brigham Young University
Active Control Of Cylindrical Shells Using The Weighted Sum Of Spatial Gradients (Wssg) Control Metric, Pegah Aslani
Theses and Dissertations
Cylindrical shells are common structures that are often used in industry, such as pipes, ducts, aircraft fuselages, rockets, submarine pressure hulls, electric motors and generators. In many applications it is desired to attenuate the sound radiated from the vibrating structure. There are both active and passive methods to achieve this purpose. However, at low frequencies passive methods are less effective and often an excessive amount of material is needed to achieve acceptable results. There have been a number of works regarding active control methods for this type of structure. In most cases a considerable number of error sensors and secondary …
Search For Gravitational Waves Associated With Gamma-Ray Bursts During The First Advanced Ligo Observing Run And Implications For The Origin Of Grb 150906b,
2017
California Institute of Technology
Search For Gravitational Waves Associated With Gamma-Ray Bursts During The First Advanced Ligo Observing Run And Implications For The Origin Of Grb 150906b, B. P. Abbott, K. Gill, B. Hughey, J. W. W. Pratt, E. Rhoades, E. Schmidt, S. G. Schwalbe, M. J. Szczepańczyk, M. Zanolin, Et Al.
Publications
We present the results of the search for gravitational waves (GWs) associated with γ-ray bursts detected during the first observing run of the Advanced Laser Interferometer Gravitational-Wave Observatory (LIGO). We find no evidence of a GW signal for any of the 41 γ-ray bursts for which LIGO data are available with sufficient duration. For all γ-ray bursts, we place lower bounds on the distance to the source using the optimistic assumption that GWs with an energy of ${10}^{-2}{M}_{\odot }{c}^{2}$ were emitted within the $16$–$500$ Hz band, and we find a median 90% confidence limit of 71 Mpc at 150 Hz. …
Search For Gravitational Waves Associated With Gamma-Ray Bursts During The First Advanced Ligo Observing Run And Implications For The Origin Of Grb 150906b,
2017
The University of Texas Rio Grande Valley
Search For Gravitational Waves Associated With Gamma-Ray Bursts During The First Advanced Ligo Observing Run And Implications For The Origin Of Grb 150906b, B. P. Abbott, Teviet Creighton, Mario C. Diaz, Joey S. Key, S. R. Morriss, Soma Mukherjee, Marc E. Normandin, Volker Quetschke, Malik Rakhmanov, Robert Stone, Darkhan Tuyenbayev, Guillermo Valdes
Physics & Astronomy Faculty Publications
We present the results of the search for gravitational waves (GWs) associated with γ-ray bursts detected during the first observing run of the Advanced Laser Interferometer Gravitational-Wave Observatory (LIGO). We find no evidence of a GW signal for any of the 41 γ-ray bursts for which LIGO data are available with sufficient duration. For all γ-ray bursts, we place lower bounds on the distance to the source using the optimistic assumption that GWs with an energy of were emitted within the-Hz band, and we find a median 90% confidence limit of 71 Mpc at 150 Hz. For the subset of …
Gw170104: Observation Of A 50-Solar-Mass Binary Black Hole Coalescence At Redshift 0.2,
2017
The University of Texas Rio Grande Valley
Gw170104: Observation Of A 50-Solar-Mass Binary Black Hole Coalescence At Redshift 0.2, B. P. Abbott, R. Abbott, Teviet Creighton, Mario C. Diaz, S. R. Morriss, Soma Mukherjee, Marc E. Normandin, Volker Quetschke, Malik Rakhmanov, Joseph D. Romano
Physics & Astronomy Faculty Publications
We describe the observation of GW170104, a gravitational-wave signal produced by the coalescence of a pair of stellar-mass black holes. The signal was measured on January 4, 2017 at 10 11:58.6 UTC by the twin advanced detectors of the Laser Interferometer Gravitational-Wave Observatory during their second observing run, with a network signal-to-noise ratio of 13 and a false alarm rate less than 1 in 70 000 years. The inferred component black hole masses are 31.2-6.0+8.4M' and 19.4-5.9+5.3M (at the 90% credible level). The black hole spins are best constrained through measurement of the effective inspiral spin parameter, a mass-weighted combination …
Book Review: Shoot The Moon: A Complete Guide To Lunar Imaging,
2017
Embry-Riddle Aeronautical University
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.
Temperature Variations In The Dayside Magnetosheath And Their Dependence On Ion-Scale Magnetic Structures: Themis Statistics And Measurements By Mms,
2017
Aalto University
Temperature Variations In The Dayside Magnetosheath And Their Dependence On Ion-Scale Magnetic Structures: Themis Statistics And Measurements By Mms, A. P. Dimmock, A. Osmane, T. I. Pulkkinen, K. Nykyri, E. Kilpua
Publications
The magnetosheath contains an array of waves, instabilities, and nonlinear magnetic structures which modify global plasma properties by means of various wave-particle interactions. The present work demonstrates that ion-scale magnetic field structures (∼0.2–0.5 Hz) observed in the dayside magnetosheath are statistically correlated to ion temperature changes on orders 10–20% of the background value. In addition, our statistical analysis implies that larger temperature changes are in equipartition to larger amplitude magnetic structures. This effect was more pronounced behind the quasi-parallel bow shock and during faster solar wind speeds. The study of two separate intervals suggests that this effect can result from …
Kepler Sheds New And Unprecedented Light On The Variability Of A Blue Supergiant: Gravity Waves In The O9.5iab Star Hd 188209,
2017
Katholieke Universiteit Leuven
Kepler Sheds New And Unprecedented Light On The Variability Of A Blue Supergiant: Gravity Waves In The O9.5iab Star Hd 188209, Conny Aerts, Sergio Símon-Díaz, Steven Bloemen, Jonas Debosscher, Péter I. Pápics, Steve Bryson, M. Still, Ehsan Moravveji, Michael H. Williamson, Frank Grundahl, Mads Fredslund Andersen, Victoria Antoci, Pere L. Pallé, Jørgen Christensen-Dalsgaard, Tamara M. Rogers
Information Systems and Engineering Management Research Publications
Stellar evolution models are most uncertain for evolved massive stars. Asteroseismology based on high-precision uninterrupted space photometry has become a new way to test the outcome of stellar evolution theory and was recently applied to a multitude of stars, but not yet to massive evolved supergiants.Our aim is to detect, analyse and interpret the photospheric and wind variability of the O9.5 Iab star HD 188209 from Kepler space photometry and long-term high-resolution spectroscopy. We used Kepler scattered-light photometry obtained by the nominal mission during 1460 d to deduce the photometric variability of this O-type supergiant. In addition, we assembled and …
An Introduction To The Quasi-Optical Design Of The Hifi Instrument For The Herschel Space Observatory,
2017
Technological University Dublin
An Introduction To The Quasi-Optical Design Of The Hifi Instrument For The Herschel Space Observatory, Gareth S. Curran, J. Anthony Murphy
The ITB Journal
This paper is concerned with the quasi-optical design and analysis of the Heterodyne Instrument for the Far Infrared (HIFI) on board the European Space Agency’s Herschel Space Observatory, which is due for launch in 2007. The paper begins with an introduction to astronomy at submillimetre wavelengths followed by the science that will be carried out by HIFI. The optical layout of HIFI is presented and the quasi-optical techniques used in the analysis of band 5 of the instrument are discussed, in particular, issues associated with the design and performance of the integrated lens antenna for this band. A power coupling …
The Stellar Initial Mass Function In Early-Type Galaxies From Absorption Line Spectroscopy. Iii. Radial Gradients,
2017
Yale University
The Stellar Initial Mass Function In Early-Type Galaxies From Absorption Line Spectroscopy. Iii. Radial Gradients, Pieter Van Dokkum, Charlie Conroy, Alexa Villaume, Jean Brodie, Aaron Romanowsky
Faculty Research, Scholarly, and Creative Activity
No abstract provided.
Atomic Data Revisions For Transitions Relevant To Observations Of Interstellar, Circumgalactic, And Intergalactic Matter,
2017
University of South Carolina
Atomic Data Revisions For Transitions Relevant To Observations Of Interstellar, Circumgalactic, And Intergalactic Matter, Frances H. Cashman, Varsha P. Kulkarni, Romas Kisielius, Gary J. Ferland, Pavel Bogdanovich
Physics and Astronomy Faculty Publications
Measurements of element abundances in galaxies from astrophysical spectroscopy depend sensitively on the atomic data used. With the goal of making the latest atomic data accessible to the community, we present a compilation of selected atomic data for resonant absorption lines at wavelengths longward of 911.753 Å (the H I Lyman limit), for key heavy elements (heavier than atomic number 5) of astrophysical interest. In particular, we focus on the transitions of those ions that have been observed in the Milky Way interstellar medium (ISM), the circumgalactic medium (CGM) of the Milky Way and/or other galaxies, and the intergalactic medium …
Retrieval Of Atmospheric Properties Of Cloudy L Dwarfs,
2017
NASA Ames Research Center
Retrieval Of Atmospheric Properties Of Cloudy L Dwarfs, Ben Burningham, M. S. Marley, M. R. Line, R. Lupu, Channon Visscher, C. V. Morley, D. Saumon, R. Freedman
Faculty Work Comprehensive List
We present the first results from applying the spectral inversion technique in the cloudy L dwarf regime. Our new framework provides a flexible approach to modelling cloud opacity which can be built incrementally as the data require and improves upon previous retrieval experiments in the brown dwarf regime by allowing for scattering in two-stream radiative transfer. Our first application of the tool to two mid-L dwarfs is able to reproduce their near-infrared spectra far more closely than grid models. Our retrieved thermal, chemical and cloud profiles allow us to estimate Teff=1796−25+23" role="presentation" style="box-sizing: border-box; margin: 0px; padding: 0px; border: 0px; …
Emission Line Ratios Of Fe Iii As Astrophysical Plasma Diagnostics,
2017
Queen's University Belfast, UK
Emission Line Ratios Of Fe Iii As Astrophysical Plasma Diagnostics, Sibasish Laha, Niall B. Tyndall, Francis P. Keenan, Connor P. Ballance, Catherine A. Ramsbottom, Gary J. Ferland, Alan Hibbert
Physics and Astronomy Faculty Publications
Recent, state-of-the-art calculations of A-values and electron impact excitation rates for Fe III are used in conjunction with the Cloudy modeling code to derive emission-line intensity ratios for optical transitions among the fine-structure levels of the 3d6 configuration. A comparison of these with high-resolution, high signal-to-noise spectra of gaseous nebulae reveals that previous discrepancies found between theory and observation are not fully resolved by the latest atomic data. Blending is ruled out as a likely cause of the discrepancies, because temperature- and density-independent ratios (arising from lines with common upper levels) match well with those predicted by theory. For …
Laminar Composite Structures For High Power Actuators,
2017
The University of Texas Rio Grande Valley
Laminar Composite Structures For High Power Actuators, M. A. Hobosyan, P. M. Martinez, A. A. Zakhidov, C. S. Haines, R. H. Baughman, K. S. Martirosyan
Physics & Astronomy Faculty Publications
Twisted laminar composite structures for high power and large-stroke actuators based on coiled Multi Wall Carbon Nanotube (MWNT) composite yarns were crafted by integrating high-density Nanoenergetic Gas Generators (NGGs) into carbon nanotube sheets. The linear actuation force, resulting from the pneumatic force caused by expanding gases confined within the pores of laminar structures and twisted carbon nanotube yarns, can be further amplified by increasing NGG loading and yarns twist density, as well as selecting NGG compositions with high energy density and large-volume gas generation. Moreover, the actuation force and power can be tuned by the surrounding environment, such as to …
Universal Disorder In Organic Semiconductors Due To Fluctuations In Space Charge,
2017
University of New Mexico
Universal Disorder In Organic Semiconductors Due To Fluctuations In Space Charge, Tzucheng Wu
Physics & Astronomy ETDs
This thesis concerns the study of charge transport in organic semiconductors. These materials are widely used as thin-film photoconductors in copiers and laser printers, and for their electroluminescent properties in organic light-emitting diodes. Much contemporary research is directed towards improving the efficiency of organic photovoltaic devices, which is limited to a large extent by the spatial and energetic disorder that hinders the charge mobility. One contribution to energetic disorder arises from the strong Coulomb interactions between injected charges with one another, but to date this has been largely ignored. We present a mean-field model for the effect of mutual interactions …
Almost Dark Galaxies: The Search For Optical Counterparts,
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,
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,
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,
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) structure and …
Literature Review: Biomimetic And Conventional Aircraft Wing Tips,
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 …
