A Feasibility Study For Using The Erau ÉChelle Spectrograph To Improve Orbital Parameters Of Spectroscopic Binary Systems,
2017
Embry-Riddle Aeronautical University
A Feasibility Study For Using The Erau ÉChelle Spectrograph To Improve Orbital Parameters Of Spectroscopic Binary Systems, Stanimir Letchev
Doctoral Dissertations and Master's Theses
Binary stars are critical for establishing knowledge of stellar masses and refining the mass-luminosity relationship when used in conjunction with precise parallax measurements. However, many spectroscopic binaries have poorly defined orbital parameters as they have not been revisited with newer CCD technology since their first observations on photographic plates. This thesis examines the feasibility of using the high-resolution échelle spectrograph at Embry-Riddle Aeronautical University (ERAU) to obtain radial velocities of spectroscopic binary stars, and establishes a software pipeline to obtain their orbital parameters. This was done by looking at the double-lined binaries HD 205539 and Pegasi, as well as the …
On The Absence Of Non-Thermal X-Ray Emission Around Runaway O Stars,
2017
Academcy Sinica
On The Absence Of Non-Thermal X-Ray Emission Around Runaway O Stars, Jesus A. Toalá, Lidia M. Oskinova, Richard Ignace
ETSU Faculty Works
Theoretical models predict that the compressed interstellar medium around runaway O stars can produce high-energy non-thermal diffuse emission, in particular, non-thermal X-ray and γ-ray emission. So far, detection of non-thermal X-ray emission was claimed for only one runaway star, AE Aur. We present a search for non-thermal diffuse X-ray emission from bow shocks using archived XMM-Newton observations for a clean sample of six well-determined runaway O stars. We find that none of these objects present diffuse X-ray emission associated with their bow shocks, similarly to previous X-ray studies toward ζ Oph and BD+43°3654. We carefully investigated multi-wavelength observations of …
Diverse Stellar Haloes In Nearby Milky Way Mass Disc Galaxies.,
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 and Staff 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 1–6 × …
Lorentz-Symmetry Test At Planck-Scale Suppression With Nucleons In A Spin-Polarized 133 Cs Cold Atom Clock,
2017
PSL Research University
Lorentz-Symmetry Test At Planck-Scale Suppression With Nucleons In A Spin-Polarized 133 Cs Cold Atom Clock, H. Pihan-Le Bars, C. Guerlin, R.-D. Lasseri, J.-P. Ebran, Q. G. Bailey, S. Bize, E. Khan, P. Wolf
Publications
The authors introduce an improved model that links the frequency of the 133 Cs hyperfine Zeeman transitions.
Ultra-Diffuse And Ultra-Compact Galaxies In The Frontier Fields Cluster Abell 2744,
2017
University of Toronto
Ultra-Diffuse And Ultra-Compact Galaxies In The Frontier Fields Cluster Abell 2744, Steven Janssens, Roberto Abraham, Jean Brodie, Duncan Forbes, Aaron Romanowsky, Pieter Van Dokkum
Faculty Publications
We report the discovery of a large population of ultra-diffuse galaxies (UDGs) in the massive galaxy cluster Abell 2744 (z = 0.308) as observed by the Hubble Frontier Fields program. Since this cluster is ~5 times more massive than Coma, our observations allow us to extend 0.7 dex beyond the high-mass end of the relationship between UDG abundance and cluster mass reported by van der Burg et al. Using the same selection criteria as van der Burg et al., A2744 hosts an estimated 1961 ± 577 UDGs, 10 times the number in Coma. As noted by Lee & Jang, A2744 …
Local Time Dependence Of Turbulent Magnetic Fields In Saturn's Magnetodisc,
2017
University of Alaska, Fairbanks
Local Time Dependence Of Turbulent Magnetic Fields In Saturn's Magnetodisc, V. Kaminker, P. A. Delamere, C. S. Ng, T. Dennis, A. Otto, X. Ma
Publications
Net plasma transport in magnetodiscs around giant planets is outward. Observations of plasma temperature have shown that the expanding plasma is heating nonadiabatically during this process. Turbulence has been suggested as a source of heating. However, the mechanism and distribution of magnetic fluctuations in giant magnetospheres are poorly understood. In this study we attempt to quantify the radial and local time dependence of fluctuating magnetic field signatures that are suggestive of turbulence, quantifying the fluctuations in terms of a plasma heating rate density. In addition, the inferred heating rate density is correlated with magnetic field configurations that include azimuthal bend …
Book Review: From The Realm Of The Nebulae To Populations Of Galaxies: Dialogues On A Century Of Research, Astrophysics And Space Science Library, 435,
2017
Embry-Riddle Aeronautical University
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
General Model For Light Curves Of Chromospherically Active Binary Stars,
2017
University of Helsinki
General Model For Light Curves Of Chromospherically Active Binary Stars, Lauri Jetsu, Gregory W. Henry, Jyri J. Lehtinen
Information Systems and Engineering Management Research Publications
The starspots on the surface of many chromospherically active binary stars concentrate on long-lived active longitudes separated by 180°. Shifts in activity between these two longitudes, the "flip-flop" events, have been observed in single stars like FK Comae and binary stars like σ Geminorum. Recently, interferometry has revealed that ellipticity may at least partly explain the flip-flop events in σ Geminorum. This idea was supported by the double-peaked shape of the long-term mean light curve of this star. Here we show that the long-term mean light curves of 14 chromospherically active binaries follow a general model that explains the connection …
X-Ray And Optical Study Of The Gamma-Ray Source 3fgl J0838.8–2829: Identification Of A Candidate Millisecond Pulsar Binary And An Asynchronous Polar,
2017
Columbia University
X-Ray And Optical Study Of The Gamma-Ray Source 3fgl J0838.8–2829: Identification Of A Candidate Millisecond Pulsar Binary And An Asynchronous Polar, Jules P. Halpern, Slavko Bogdanov, John R. Thorstensen
Dartmouth Scholarship
We observed the field of the Fermi source 3FGL J0838.8−2829 in optical and X-rays, initially motivated by the cataclysmic variable (CV) 1RXS J083842.1−282723 that lies within its error circle. Several X-ray sources first classified as CVs have turned out to be γ-ray emitting millisecond pulsars (MSPs). We find that 1RXS J083842.1−282723 is in fact an unusual CV, a stream-fed asynchronous polar in which accretion switches between magnetic poles (that are ≈120° apart) when the accretion rate is at minimum. High-amplitude X-ray modulation at periods of 94.8 ± 0.4 minutes and 14.7 ± 1.2 hr are seen. The former appears …
A Differential Abundance Analysis Of Very Metal-Poor Stars,
2017
Dartmouth College
A Differential Abundance Analysis Of Very Metal-Poor Stars, Erin M. O'Malley, Andrew Mcwilliam, Brian Chaboyer, Ian Thompson
Dartmouth Scholarship
We have performed a differential line-by-line chemical abundance analysis, ultimately relative to the Sun, of nine very metal-poor main-sequence (MS) halo stars, near [Fe/H] = −2 dex. Our abundances range from dex with conservative uncertainties of 0.07 dex. We find an average [α/Fe] = 0.34 ± 0.09 dex, typical of the Milky Way. While our spectroscopic atmosphere parameters provide good agreement with Hubble Space Telescope parallaxes, there is significant disagreement with temperature and gravity parameters indicated by observed colors and theoretical isochrones. Although a systematic underestimate of the stellar temperature by a few hundred degrees could explain this …
Calibration Of The Advanced Ligo Detectors For The Discovery Of The Binary Black-Hole Merger Gw150914,
2017
The University of Texas Rio Grande Valley
Calibration Of The Advanced Ligo Detectors For The Discovery Of The Binary Black-Hole Merger Gw150914, B. P. Abbott, R. Abbott, T. D. Abbott, M. R. Abernathy, K. Ackley, Mario C. Diaz, Joey S. Key, Soma Mukherjee, Volker Quetschke, Malik Rakhmanov
Physics & Astronomy Faculty Publications
In Advanced LIGO, detection and astrophysical source parameter estimation of the binary black hole merger GW150914 requires a calibrated estimate of the gravitational-wave strain sensed by the detectors. Producing an estimate from each detector's differential arm length control loop readout signals requires applying time domain filters, which are designed from a frequency domain model of the detector's gravitational-wave response. The gravitational-wave response model is determined by the detector's opto-mechanical response and the properties of its feedback control system. The measurements used to validate the model and characterize its uncertainty are derived primarily from a dedicated photon radiation pressure actuator, with …
A Hierarchical Model For The Ages Of Galactic Halo White Dwarfs,
2017
Imperial College London
A Hierarchical Model For The Ages Of Galactic Halo White Dwarfs, Shijing Si, Ted Von Hippel, David A. Van Dyk, Elliot Robinson, Aaron Webster, Et Al.
Publications
In astrophysics, we often aim to estimate one or more parameters for each member object in a population and study the distribution of the fitted parameters across the population. In this paper, we develop novel methods that allow us to take advantage of existing software designed for such case-by-case analyses to simultaneously fit parameters of both the individual objects and the parameters that quantify their distribution across the population. Our methods are based on Bayesian hierarchical modelling which is known to produce parameter estimators for the individual objects that are on average closer to their true values than estimators based …
A Local Leaky-Box Model For The Local Stellar Surface Density-Gas Surface Density-Gas Phase Metallicity Relation,
2017
Johns Hopkins University
A Local Leaky-Box Model For The Local Stellar Surface Density-Gas Surface Density-Gas Phase Metallicity Relation, Guangtun Ben Zhu, Jorge K. Barrera-Ballesteros, Timothy M. Heckman, Nadia L. Zakamska, Sebastian F. Sánchez, Renbin Yan, Jonathan Brinkman
Physics and Astronomy Faculty Publications
We revisit the relation between the stellar surface density, the gas surface density and the gas-phase metallicity of typical disc galaxies in the local Universe with the SDSS-IV/MaNGA survey, using the star formation rate surface density as an indicator for the gas surface density. We show that these three local parameters form a tight relationship, confirming previous works (e.g. by the PINGS and CALIFA surveys), but with a larger sample. We present a new local leaky-box model, assuming star-formation history and chemical evolution is localized except for outflowing materials. We derive closed-form solutions for the evolution of stellar surface density, …
Upper Limits On The Stochastic Gravitational-Wave Background From Advanced Ligo's First Observing Run,
2017
The University of Texas Rio Grande Valley
Upper Limits On The Stochastic Gravitational-Wave Background From Advanced Ligo's First Observing Run, B. P. Abbott, Teviet Creighton, Mario C. Diaz, S. R. Morriss, Soma Mukherjee, Marc E. Normandin, Volker Quetschke, Malik Rakhmanov, Joseph D. Romano, Robert Stone, Darkhan Tuyenbayev, Guillermo Valdes
Physics & Astronomy Faculty Publications
A wide variety of astrophysical and cosmological sources are expected to contribute to a stochastic gravitational-wave background. Following the observations of GW150914 and GW151226, the rate and mass of coalescing binary black holes appear to be greater than many previous expectations. As a result, the stochastic background from unresolved compact binary coalescences is expected to be particularly loud. We perform a search for the isotropic stochastic gravitational-wave background using data from Advanced Laser Interferometer Gravitational Wave Observatory's (aLIGO) first observing run. The data display no evidence of a stochastic gravitational-wave signal. We constrain the dimensionless energy density of gravitational waves …
Directional Limits On Persistent Gravitational Waves From Advanced Ligo's First Observing Run,
2017
The University of Texas Rio Grande Valley
Directional Limits On Persistent Gravitational Waves From Advanced Ligo's First Observing Run, B. P. Abbott, Teviet Creighton, Mario C. Diaz, S. R. Morriss, Soma Mukherjee, Marc E. Normandin, Volker Quetschke, Malik Rakhmanov, Joseph D. Romano, Robert Stone, Darkhan Tuyenbayev, Guillermo Valdes
Physics & Astronomy Faculty Publications
We employ gravitational-wave radiometry to map the stochastic gravitational wave background expected from a variety of contributing mechanisms and test the assumption of isotropy using data from the Advanced Laser Interferometer Gravitational Wave Observatory’s (aLIGO) first observing run. We also search for persistent gravitational waves from point sources with only minimal assumptions over the 20–1726 Hz frequency band. Finding no evidence of gravitational waves from either point sources or a stochastic background, we set limits at 90% confidence. For broadband point sources, we report upper limits on the gravitational wave energy flux per unit frequency in the range Fα,Θ(f)
Corrigendum To “On High Order Finite-Difference Metric Discretizations Satisfying Gcl On Moving And Deforming Grids” [J. Comput.Phys. 265 (2014) 211–220],
2017
Lawrence Livermore National Laboratory, Livermore
Corrigendum To “On High Order Finite-Difference Metric Discretizations Satisfying Gcl On Moving And Deforming Grids” [J. Comput.Phys. 265 (2014) 211–220], Björn Sjögreen, H.C. Yee, Marcel Vinokur
United States National Aeronautics and Space Administration: Publications
The authors regret that the already published version contains some typographic errors in the formulas for the Runge-Kutta moving metric time stepping method.
The Composition Of Comet C/2012 K1 (Panstarrs) And The Distribution Of Primary Volatile Abundances Among Comets,
2017
University of Missouri–St. Louis
The Composition Of Comet C/2012 K1 (Panstarrs) And The Distribution Of Primary Volatile Abundances Among Comets, Nathan Roth, Erika Gibb, Boncho Bonev, Michael Disanti, Michael Mumma, Geronimo Villanueva, Lucas Paganini
Physics Faculty Works
On 2014 May 22 and 24 we characterized the volatile composition of the dynamically new Oort cloud comet C/2012 K1 (PanSTARRS) using the long-slit, high resolution (λ/Δλ ≈ 25,000) near-infrared echelle spectrograph (NIRSPEC) at the 10 m Keck II telescope on Maunakea, Hawaii. We detected fluorescent emission from six primary volatiles (H2O, HCN, CH4, C2H6, CH3OH, and CO). Upper limits were derived for C2H2, NH3, and H2CO. We report rotational temperatures, production rates, and mixing ratios (relative to water). Compared with median abundance ratios for primary volatiles in other sampled Oort cloud comets, trace gas abundance ratios in C/2012 K1 …
Which Stars Are Ionizing The Orion Nebula?,
2017
Vanderbilt University
Which Stars Are Ionizing The Orion Nebula?, C. R. O'Dell, W. Kollatschny, Gary J. Ferland
Physics and Astronomy Faculty Publications
The common assumption that θ1 Ori C is the dominant ionizing source for the Orion Nebula is critically examined. This assumption underlies much of the existing analysis of the nebula. In this paper we establish through comparison of the relative strengths of emission lines with expectations from Cloudy models and through the direction of the bright edges of proplyds that θ2 Ori A, which lies beyond the Bright Bar, also plays an important role. θ1 Ori C does dominate ionization in the inner part of the Orion Nebula, but outside of the Bright Bar as far as …
The X-Ray And Mid-Infrared Luminosities In Luminous Type 1 Quasars,
2017
Dartmouth College
The X-Ray And Mid-Infrared Luminosities In Luminous Type 1 Quasars, Chien-Ting J. Chen, Ryan C. Hickox, Andrew D. Goulding, Daniel Stern
Dartmouth Scholarship
Several recent studies have reported different intrinsic correlations between the AGN mid-IR luminosity (LMIR) and the rest-frame 2-10 keV luminosity (LX) for luminous quasars. To understand the origin of the difference in the observed LX−LMIR relations, we study a sample of 3,247 spectroscopically confirmed type 1 AGNs collected from Bo\"{o}tes, XMM-COSMOS, XMM-XXL-North, and the SDSS quasars in the Swift/XRT footprint spanning over four orders of magnitude in luminosity. We carefully examine how different observational constraints impact the observed LX−LMIR relations, including the inclusion of X-ray non-detected objects, possible X-ray absorption …
Space Telescope And Optical Reverberation Mapping Project. V. Optical Spectroscopic Campaign And Emission-Line Analysis For Ngc 5548,
2017
University of California - Irvine
Space Telescope And Optical Reverberation Mapping Project. V. Optical Spectroscopic Campaign And Emission-Line Analysis For Ngc 5548, L. Pei, M. M. Fausnaugh, A. J. Barth, B. M. Peterson, M. C. Bentz, G. De Rosa, K. D. Denney, M. R. Goad, C. S. Kochanek, K. T. Korista, G. A. Kriss, R. W. Pogge, V. N. Bennert, M. Brotherton, K. I. Clubb, E. Dalla Bontà, A. V. Filippenko, J. E. Greene, C. J. Grier, M. Vestergaard, W. Zheng, Scott M. Adams, Thomas G. Beatty, A. Bigley, Jacob E. Brown, Jonathan S. Brown, G. Canalizo, J. M. Comerford, Carl T. Coker, E. M. Corsini, Gary J. Ferland, S. A. Klimanov
Physics and Astronomy Faculty Publications
We present the results of an optical spectroscopic monitoring program targeting NGC 5548 as part of a larger multiwavelength reverberation mapping campaign. The campaign spanned 6 months and achieved an almost daily cadence with observations from five ground-based telescopes. The Hβ and He ii λ4686 broad emission-line light curves lag that of the 5100 Å optical continuum by 4.17+0.36 -0.36 days and 0.79+0.35-0.34 days respectively. The Hβ lag relative to the 1158 Å ultraviolet continuum light curve measured by the Hubble Space Telescope is ~50% longer than that measured against the optical continuum, and …
