Herschel Observations Of Edge-On Spirals (Heroes) I. Far-Infrared Morphology And Dust Mass Determination.,
2013
Universiteit Gent
Herschel Observations Of Edge-On Spirals (Heroes) I. Far-Infrared Morphology And Dust Mass Determination., J. Verstappen, J. Fritz, M. Baes, M. W. L. Smith, F. Allaert, S. Bianchi, J. A. D. L. Blommaert, G. De Geyter, I. De Looze, G. Gentile, K. D. Gordon, Benne W. Holwerda, S. Viaene, E. M. Xilouris
Faculty and Staff Scholarship
Context. Edge-on spiral galaxies with prominent dust lanes provide us with an excellent opportunity to study the distribution and properties of the dust within them. The HEROES project was set up to observe a sample of seven large edge-on galaxies across various wavelengths for this investigation. Aims. Within this first paper, we present the Herschel observations and perform a qualitative and quantitative analysis on them, and we derive some global properties of the far infrared and submillimetre emission. Methods. We determine horizontal and vertical profiles from the Herschel observations of the galaxies in the sample and describe the morphology. Modified …
On The Origin Of Lopsidedness In Galaxies As Determined From The Spitzer Survey Of Stellar Structure In Galaxies (S4g).,
2013
University of Arizona
On The Origin Of Lopsidedness In Galaxies As Determined From The Spitzer Survey Of Stellar Structure In Galaxies (S4g)., Dennis Zaritsky, Heikki Salo, Eija Laurikainen, Debra M. Elmegreen, E. Athanassoula, Albert Bosma, Sebastien Comeron, Santiago Erroz-Ferrer, Bruce G. Elmegreen, Dimitri A. Gadotti, Armando Gil De Paz, Joannah L. Hinz, Luis C. Ho, Benne W. Holwerda, Taehyun Kim, Johan H. Knapen, Jarkko Laine, Seppo Laine, Barry F. Madore, Sharon Meidt, Karin Menendez-Delmestre, Trisha Mizusawa, Juan Carlos Munoz-Mateos, Michael W. Regan, Mark Seibert, Kartik Sheth
Faculty and Staff Scholarship
We study the m = 1 distortions (lopsidedness) in the stellar components of 167 nearby galaxies that span a wide range of morphologies and luminosities. We confirm the previous findings of (1) a high incidence of lopsidedness in the stellar distributions, (2) increasing lopsidedness as a function of radius out to at least 3.5 exponential scale lengths, and (3) greater lopsidedness, over these radii, for galaxies of later type and lower surface brightness. Additionally, the magnitude of the lopsidedness (1) correlates with the character of the spiral arms (stronger arm patterns occur in galaxies with less lopsidedness), (2) is not …
A Detailed Kinematic Map Of Cassiopeia A'S Optical Main Shell And Outer High-Velocity Ejecta,
2013
Harvard University
A Detailed Kinematic Map Of Cassiopeia A'S Optical Main Shell And Outer High-Velocity Ejecta, Dan Milisavljevic, Robert A. Fesen
Dartmouth Scholarship
We present three-dimensional (3D) kinematic reconstructions of optically emitting material in the young Galactic supernova remnant Cassiopeia A (Cas A). These Doppler maps have the highest spectral and spatial resolutions of any previous survey of Cas A and represent the most complete catalog of its optically emitting material to date. We confirm that the bulk of Cas A’s optically bright ejecta populate a torus-like geometry tilted approximately 30◦ with respect to the plane of the sky with a − 4000 to +6000 km s−1 radial velocity asymmetry. Near-tangent viewing angle effects and an inhomogeneous surrounding circumstellar material/ interstellar medium environment …
Design And Evaluation Of A Fiber Optic Probe As A Means Of Subsurface Planetary Exploration,
2013
University of Arkansas, Fayetteville
Design And Evaluation Of A Fiber Optic Probe As A Means Of Subsurface Planetary Exploration, Robert Paul Pilgrim
Graduate Theses and Dissertations
The Optical Probe for Regolith Analysis (OPRA) is an instrumentation concept designed to provide spectroscopic analysis of the near subsurface of unconsolidated regolith on bodies such as moons, asteroids and planets. Below a chemically altered surface may lay the geological history in the form of stratigraphy that is shielded from degradation due to harsh external environments. Most of what we know about our solar system comes from remote platforms, such as satellites that are deployed into orbit around the target body. In the case of Mars, we have had several successful landers and rovers however, with the exception of the …
Mechanisms Of Field-Aligned Current Formation In Magnetic Reconnection,
2013
University of Alaska, Fairbanks
Mechanisms Of Field-Aligned Current Formation In Magnetic Reconnection, Xuanye Ma, Antonius Otto
Publications
Satellite observations provide strong evidence for the generation of significant field-aligned currents (FACs) during magnetic reconnection. Reconnection of antiparallel magnetic field does not generate FACs in magnetohydrodynamics (MHD) due to coplanarity in MHD shocks. However, a guide magnetic field and a sheared velocity component are almost always present at the magnetopause and their absence is a singular case. It is illustrated that the presence of these noncoplanar fields requires FACs. Contrary to intuition, such currents are generated more efficiently for a small guide field and are more likely to be a result of the redistribution of already present FACs for …
An Hst Optical-To-Near-Ir Transmission Spectrum Of The Hot Jupiter Wasp-19b: Detection Of Atmospheric Water And Likely Absence Of Tio,
2013
University of Exeter
An Hst Optical-To-Near-Ir Transmission Spectrum Of The Hot Jupiter Wasp-19b: Detection Of Atmospheric Water And Likely Absence Of Tio, Catherine M. Huitson, David K. Sing, Frederic Pont, Jonathan J. Fortney, Adam Burrows, Paul A. Wilson, Gilda E. Ballester, Nikolay Nikolov, Neale P. Gibson, Drake Deming, Suzanne Aigrain, Thomas M. Evans, Gregory W. Henry, Alain Lecavelier Des Etangs, Adam P. Showman, Alfred Vidal-Madjar, Kevin J. Zahnle
Information Systems and Engineering Management Research Publications
We measure the transmission spectrum of WASP-19b from three transits using low-resolution optical spectroscopy from the Hubble Space Telescope (HST) Space Telescope Imaging Spectrograph (STIS). The STIS spectra cover a wavelength range of 0.29–1.03 μm, with resolving power R = 500. The optical data are combined with archival near-infrared data from the HST Wide Field Camera 3 (WFC3) G141 grism, covering the wavelength range from 1.087 to 1.687 μm, with resolving power R = 130. We reach signal-to-noise levels between 3000 and 11 000 in 0.1 μm bins when measuring the transmission spectra from 0.53–1.687 μm. WASP-19 is known to …
Fluctuation-Dissipation Theorem In An Isolated System Of Quantum Dipolar Bosons After A Quench,
2013
University of California, Santa Cruz
Fluctuation-Dissipation Theorem In An Isolated System Of Quantum Dipolar Bosons After A Quench, Ehsan Khatami, Guido Pupillo, Mark Srednicki, Marcos Rigol
Faculty Publications
We examine the validity of fluctuation-dissipation relations in isolated quantum systems taken out of equilibrium by a sudden quench. We focus on the dynamics of trapped hard-core bosons in one-dimensional lattices with dipolar interactions whose strength is changed during the quench. We find indications that fluctuation-dissipation relations hold if the system is nonintegrable after the quench, as well as if it is integrable after the quench if the initial state is an equilibrium state of a nonintegrable Hamiltonian. On the other hand, we find indications that they fail if the system is integrable both before and after quenching.
A Quasar–Galaxy Mixing Diagram: Quasar Spectral Energy Distribution Shapes In The Optical To Near-Infrared,
2013
Harvard–Smithsonian Center for Astrophysics
A Quasar–Galaxy Mixing Diagram: Quasar Spectral Energy Distribution Shapes In The Optical To Near-Infrared, Heng Hao, Martin Elvis, Angela Bongiorno, Gianni Zamorani, Andrea Merloni, C. Kelly, Francesca Civano
Dartmouth Scholarship
We define a quasar–galaxy mixing diagram using the slopes of their spectral energy distributions (SEDs) from 1 μm to 3000 Å and from 1 to 3 μm in the rest frame. The mixing diagram can easily distinguish among quasar-dominated, galaxy-dominated and reddening-dominated SED shapes. By studying the position of the 413 XMM-selected type 1 AGN in the wide-field ‘Cosmic Evolution Survey’ in the mixing diagram, we find that a combination of the Elvis et al. mean quasar SED with various contributions from galaxy emission and some dust reddening is remarkably effective in describing the SED shape from 0.3 to …
Interstellar H2O Masers From J Shocks,
2013
SETI Institute
Interstellar H2O Masers From J Shocks, David Hollenbach, Moshe Elitzur, Christopher F. Mckee
Physics and Astronomy Faculty Publications
We present a model in which the 22 GHz H2O masers observed in star-forming regions occur behind shocks propagating in dense regions (preshock density n 0 ~ 106-108 cm–3). We focus on high-velocity (vs ≳ 30 km s–1) dissociative J shocks in which the heat of H2 re-formation maintains a large column of ~300-400 K gas; at these temperatures the chemistry drives a considerable fraction of the oxygen not in CO to form H2O. The H2O column densities, the hydrogen densities, and the warm …
The Jet-Disk Connection: Evidence For A Reinterpretation In Radio-Loud And Radio-Quiet Active Galactic Nuclei,
2013
Kennesaw State University
The Jet-Disk Connection: Evidence For A Reinterpretation In Radio-Loud And Radio-Quiet Active Galactic Nuclei, David Garofalo
Faculty Articles
To constrain models of the jet-disc connection, we explore Eddington ratios reported in Foschini (2011) and interpret them in relation to the values in Sikora et al. across the active galactic nuclei population from radio loud quasars, their flat spectrum radio quasar subclass, the recently discovered gamma-ray loud narrow-line type 1 Seyfert galaxies, Fanaroff-Riley type I (FRI) radio galaxies and radio quiet quasars of the Palomar Green survey. While appeal to disc truncation in radiatively inefficient flow appears to explain the observed inverse relation between radio loudness and Eddington ratio in radio loud and radio quiet quasars, FR I objects, …
1es 1927+654: A Bare Seyfert 2,
2013
Saint Mary's University, Halifax, NS, Canada
1es 1927+654: A Bare Seyfert 2, L. C. Gallo, C. Macmackin, R. Vasudevan, E. M. Cackett, A. C. Fabian, F. Panessa
Physics and Astronomy Faculty Research Publications
1ES 1927+654 is an active galactic nucleus (AGN) tbat appears to defy the unification model. It exhibits a type-2 optical spectrum, but possesses little X-ray obscuration. XMM-Newton and Suzaku observations obtained in 2011 are used to study the X-ray properties of 1ES 1927+654. The spectral energy distribution derived from simultaneous optical-to-X-ray data obtained with XMM-Newton shows that the AGN has a typical Eddington ratio (L/LEdd = 0.014 ··· 0.11). The X-ray spectrum and rapid variability are consistent with originating from a corona surrounding a standard accretion disc. Partial covering models can describe the X-ray data: however, the narrow …
The Importance Of Major Mergers In The Build Up Of Stellar Mass In Brightest Cluster Galaxies At Z = 1,
2013
Australian Astronomical Observatory, Australia
The Importance Of Major Mergers In The Build Up Of Stellar Mass In Brightest Cluster Galaxies At Z = 1, C. Lidman, G. Iacobuta, A. E. Bauer, L. F. Barrientos, P. Cerulo, W. J. Couch, L. Delaye, R. Demarco, E. Ellingson, A. J. Faloon, D. Gilbank, M. Huertas-Company, S. Mei, J. Meyers, A. Muzzin, A. Noble, J. Nantais, A. Rettura, P. Rosati, R. Sánchez-Janssen, V. Strazzullo, T. M. A. Webb, G. Wilson, Renbin Yan, H. K. C. Yee
Physics and Astronomy Faculty Publications
Recent independent results from numerical simulations and observations have shown that brightest cluster galaxies (BCGs) have increased their stellar mass by a factor of almost 2 between z ∼ 0.9 and z ∼ 0.2. The numerical simulations further suggest that more than half this mass is accreted through major mergers. Using a sample of 18 distant galaxy clusters with over 600 spectroscopically confirmed cluster members between them, we search for observational evidence that major mergers do play a significant role. We find a major merger rate of 0.38 ± 0.14 mergers per Gyr at z ∼ 1. While the uncertainties, …
Timing And Interstellar Scattering Of 35 Distant Pulsars Discovered In The Palfa Survey,
2013
The University of Texas Rio Grande Valley
Timing And Interstellar Scattering Of 35 Distant Pulsars Discovered In The Palfa Survey, D. J. Nice, E. Altiere, S. Bogdanov, J. M. Cordes, D. Farrington, J. W.T. Hessels, V. M. Kaspi, A. G. Lyne, Fredrick A. Jenet, Kevin Stovall
Physics & Astronomy Faculty Publications
We have made extensive observations of 35 distant slow (non-recycled) pulsars discovered in the ongoing Arecibo PALFA pulsar survey. Timing observations of these pulsars over several years at Arecibo Observatory and Jodrell Bank Observatory have yielded high-precision positions and measurements of rotation properties. Despite being a relatively distant population, these pulsars have properties that mirror those of the previously known pulsar population. Many of the sources exhibit timing noise, and one underwent a small glitch. We have used multifrequency data to measure the interstellar scattering properties of these pulsars. We find scattering to be higher than predicted along some lines …
Orbital, Superhump And Superorbital Periods In The Cataclysmic Variables Aq Mensae And Im Eridani,
2013
University of California - San Diego
Orbital, Superhump And Superorbital Periods In The Cataclysmic Variables Aq Mensae And Im Eridani, E. Armstrong, J. Patterson, E. Michelsen, John Thorstensen
Dartmouth Scholarship
We report photometric detections of orbital and superorbital signals, and negative orbital sidebands, in the light curves of the nova-like cataclysmic variables AQ Mensae and IM Eridani. The frequencies of the orbital, superorbital, and sideband signals are 7.0686 (3), 0.263 (3), and 7.332 (3) cycles per day (c/d) in AQ Mensae, and 6.870 (1), 0.354 (7), and 7.226 (1) c/d in IM Eridani. We also find a spectroscopic orbital frequency in IM Eridani of 6.86649 (2) c/d. These observations can be reproduced by invoking an accretion disc that is tilted with respect to the orbital plane. This model works well …
Stellar Populations And The Star Formation Histories Of Low Surface Brightness Galaxies. Ii. H Ii Regions,
2013
Case Western Reserve University
Stellar Populations And The Star Formation Histories Of Low Surface Brightness Galaxies. Ii. H Ii Regions, Stacy S. Mcgaugh
Faculty Scholarship
The luminosities, colors, and Ha emission for 429 H II regions in 54 low surface brightness (LSB) galaxies are presented. While the number of H II regions per galaxy is lower in LSB galaxies compared to star-forming irregulars and spirals, there is no indication that the size or luminosity function of H II regions differs from other galaxy types. The lower number of Hii regions per galaxy is consistent with their lower total star formation rates. The fraction of the total LH α contributed by H II regions varies from 10% to 90% in LSB galaxies (the rest of the …
Field Localization And The Nambu-Jona-Lasinio Mass Generation Mechanism In An Alternative 5-Dimensional Brane Model,
2013
California State University, Fresno
Field Localization And The Nambu-Jona-Lasinio Mass Generation Mechanism In An Alternative 5-Dimensional Brane Model, Preston Jones, Gerardo Muñoz, Douglas Singleton, Triyanta
Publications
We consider a five-dimensional brane world model with a single brane which is distinct from the well known Randall-Sundrum model. We discuss the similarities and differences between our brane model and the Randall-Sundrum brane model. In particular we focus on the localization of five-dimensional fields with different spins—spin 0, spin 1 / 2 , and spin 1—to the brane, and a self-consistent mass-generation mechanism. We find that the brane model studied here has different (and in some cases superior) localization properties for fields/particles with different spins to the brane, as compared to the original five-dimensional brane models. In addition this …
Use Of Support Vector Machines And Fabry-Perot Interferometry To Classify States Of A Laser,
2013
Eastern Michigan University
Use Of Support Vector Machines And Fabry-Perot Interferometry To Classify States Of A Laser, John Motley Mckinnon
Master's Theses and Doctoral Dissertations
This thesis develops an algorithm that can determine if a laser is functioning correctly over a long period of time. A Fourier fit is created to model fringe profiles from a Fabry-Perot interferometer, and singular value decomposition is used to reduce noise in each signal. Levenberg-Marquardt gradient descent is performed to correctly locate the center of each image and to optimize each fit with respect to the spatial frequency. The Fourier fit is used to extract important information from each image to be used for separating the image types from one another. Principal component analysis is used to reduce the …
Analyses Of Nonlinearity Measures In High-Amplitude Sound Propagation,
2013
Brigham Young University - Provo
Analyses Of Nonlinearity Measures In High-Amplitude Sound Propagation, Michael B. Muhlestein
Theses and Dissertations
Military aircraft generate high-amplitude noise which can cause injury to attending personnel. Efforts to mitigate the effects of this noise require a detailed understanding of the propagation of the noise, which was shown previously to be nonlinear. This thesis presents an analysis of high-amplitude noise propagation, emphasizing measures used to quantify the importance of considering nonlinearity. Two measures of the importance of nonlinearity are compared. These measures are the wave steepening factor and a skewness estimate. The wave steepening factor is a measure of how much nonlinear waveform steepening has occurred in a waveform. The skewness estimate is the skewness …
Understanding The Origin Of The [Oi] Low-Velocity Component From T Tauri Stars,
2013
University of Arizona
Understanding The Origin Of The [Oi] Low-Velocity Component From T Tauri Stars, Elisabetta Rigliaco, Ilaria Pascucci, Uma Gorti, Suzan Edwards, D. Hollenbach
Astronomy: Faculty Publications
The formation time, masses, and location of planets are strongly impacted by the physical mechanisms that disperse protoplanetary disks and the timescale over which protoplanetary material is cleared out. Accretion of matter onto the central star, protostellar winds/jets, magnetic disk winds, and photoevaporative winds operate concurrently. Hence, disentangling their relative contribution to disk dispersal requires identifying diagnostics that trace different star–disk environments. Here, we analyze the low-velocity component (LVC) of the oxygen optical forbidden lines, which is found to be blueshifted by a few km s−1 with respect to the stellar velocity. We find that the [O i] LVC …
Characterization Of Ingaas Quantum Dot Chains,
2013
Brigham Young University - Provo
Characterization Of Ingaas Quantum Dot Chains, Tyler Drue Park
Theses and Dissertations
InGaAs quantum dot chains were grown with a low-temperature variation of the Stranski-Krastanov method, the conventional epitaxial method. This new method seeks to reduce indium segregation and intermixing in addition to giving greater control in the growth process. We used photoluminescence spectroscopy techniques to characterize the quality and electronic structure of these samples. We have recently used a transmission electron microscope to show how the quantum dots vary with annealing temperature. Some questions relating to the morphology of the samples cannot be answered by photoluminescence spectroscopy alone. Using transmission electron microscopy, we verified flattening of the quantum dots with annealing …
