Einstein A Coefficients And Oscillator Strengths For The A 2Π-X2Σ+ (Red) And B 2Σ+-X2Σ+ (Violet) Systems And Rovibrational Transitions In The X2Σ+ State Of Cn,
2014
Old Dominion University
Einstein A Coefficients And Oscillator Strengths For The A 2Π-X2Σ+ (Red) And B 2Σ+-X2Σ+ (Violet) Systems And Rovibrational Transitions In The X2Σ+ State Of Cn, James S. A. Brooke, Ram S. Ram, Colin M. Western, Gang Li, David W. Schwenke, Peter F. Bernath
Chemistry & Biochemistry Faculty Publications
Line strengths have been calculated in the form of Einstein A coefficients and f-values for a large number of bands of the A 2Π-X 2Σ+ and B 2Σ+-X 2Σ+ systems and rovibrational transitions within the X 2Σ+ state of CN using Western's PGOPHER program. The J dependence of the transition dipole moment matrix elements (the Herman-Wallis effect) has been taken into account. Rydberg-Klein-Rees potential energy functions for the A 2Π, B 2Σ+ , and X 2Σ+ states were computed using spectroscopic constants from the …
Planetary Candidates Observed By Kepler Iv: Planet Sample From Q1-Q8 (22 Months),
2014
SETI Institute/NASA Ames Research Center
Planetary Candidates Observed By Kepler Iv: Planet Sample From Q1-Q8 (22 Months), Christopher J. Burke, Darin Ragozzine
Aerospace, Physics, and Space Science Faculty Publications
We provide updates to the Kepler planet candidate sample based upon nearly two years of high-precision photometry (i.e., Q1-Q8). From an initial list of nearly 13,400 threshold crossing events, 480 new host stars are identified from their flux time series as consistent with hosting transiting planets. Potential transit signals are subjected to further analysis using the pixel-level data, which allows background eclipsing binaries to be identified through small image position shifts during transit. We also re-evaluate Kepler Objects of Interest (KOIs) 1-1609, which were identified early in the mission, using substantially more data to test for background false positives and …
Dilute Magnetism And Spin-Orbital Percolation Effects In Sr2Ir1−XRhXO4,
2014
University of Toronto, Canada
Dilute Magnetism And Spin-Orbital Percolation Effects In Sr2Ir1−XRhXO4, J. P. Clancy, A. Lupascu, H. Gretarsson, Z. Islam, Y. F. Hu, D. Casa, C. S. Nelson, S. C. Lamarra, Gang Cao, Young-June Kim
Physics and Astronomy Faculty Publications
We have used a combination of resonant magnetic x-ray scattering and x-ray absorption spectroscopy to investigate the properties of the doped spin-orbital Mott insulator Sr2Ir1−xRhxO4 (0.07 ≤ x ≤ 0.70). We show that Sr2Ir1−xRhxO4 represents a unique model system for the study of dilute magnetism in the presence of strong spin-orbit coupling, and provide evidence of a doping-induced change in magnetic structure and a suppression of magnetic order at xc ∼ 0.17. We demonstrate that Rh-doping introduces Rh3+/Ir5+ ions which …
Novel Magnetism Of Ir5+(5D4) Ions In The Double Perovskite Sr2Yiro6,
2014
University of Kentucky
Novel Magnetism Of Ir5+(5D4) Ions In The Double Perovskite Sr2Yiro6, Gang Cao, Tongfei Qi, Li Li, Jsaminka Terzic, Shujuan Yuan, Lance E. De Long, Ganpathy Murthy, Ribhu K. Kaul
Physics and Astronomy Faculty Publications
We synthesize and study single crystals of a new double-perovskite Sr2YIrO6. Despite two strongly unfavorable conditions for magnetic order, namely, pentavalent Ir5+(5d4) ions which are anticipated to have Jeff=0 singlet ground states in the strong spin-orbit coupling (SOC) limit and geometric frustration in a face-centered cubic structure formed by the Ir5+ ions, we observe this iridate to undergo a novel magnetic transition at temperatures below 1.3 K. We provide compelling experimental and theoretical evidence that the origin of magnetism is in an unusual interplay between strong noncubic crystal …
Interaction Of Magnetic Reconnection And Kelvin-Helmholtz Modes For Large Magnetic Shear: 2. Reconnection Trigger,
2014
University of Alaska, Fairbanks
Interaction Of Magnetic Reconnection And Kelvin-Helmholtz Modes For Large Magnetic Shear: 2. Reconnection Trigger, Xuanye Ma, Antonius Otto, Peter A. Delamere
Publications
A typical property of magnetopause reconnection is a significant perpendicular shear flow due to the fast streaming magnetosheath plasma. Therefore, the magnetopause represents a large magnetic and flow shear boundary during periods of southward interplanetary magnetic field, which can be unstable to Kelvin‐Helmholtz (KH) modes and to magnetic reconnection. A series of local three‐dimensional MHD and Hall MHD simulations is carried out to investigate the interaction of reconnection and nonlinear KH waves considering magnetic reconnection as the primary process. It is demonstrated that the onset reconnection causes a thinning of the shear flow layer, thereby generating small wavelength KH modes. …
Evidence For A Weak Wind From The Young Sun,
2014
Naval Research Laboratory
Evidence For A Weak Wind From The Young Sun, Brian E. Wood, Hans-Reinhard Müller, Seth Redfield, Eric Edelman
Dartmouth Scholarship
The early history of the solar wind has remained largely a mystery due to the difficulty of detecting winds around young stars that can serve as analogs for the young Sun. Here we report on the detection of a wind from the 500 Myr old solar analog π1 UMa (G1.5 V), using spectroscopic observations from the Hubble Space Telescope. We detect H I Lyα absorption from the interaction region between the stellar wind and interstellar medium, i.e., the stellar astrosphere. With the assistance of hydrodynamic models of the π1 UMa astrosphere, we infer a wind only half as strong as …
Searching For Pulsars Using Image Pattern Recognition,
2014
The University of Texas Rio Grande Valley
Searching For Pulsars Using Image Pattern Recognition, W. W. Zhu, Kevin Stovall, Stephanie Cohen, Louis Percy Dartez, Grady Lunsford, Jose Guadalupe Martinez, Alberto Mata, Fredrick A. Jenet
Physics & Astronomy Faculty Publications
In the modern era of big data, many fields of astronomy are generating huge volumes of data, the analysis of which can sometimes be the limiting factor in research. Fortunately, computer scientists have developed powerful data-mining techniques that can be applied to various fields. In this paper, we present a novel artificial intelligence (AI) program that identifies pulsars from recent surveys by using image pattern recognition with deep neural nets - the PICS (Pulsar Image-based Classification System) AI. The AI mimics human experts and distinguishes pulsars from noise and interference by looking for patterns from candidate plots. Different from other …
Galaxy And Mass Assembly (Gama) : Mid-Infrared Properties And Empirical Relations From Wise.,
2014
University of Cape Town
Galaxy And Mass Assembly (Gama) : Mid-Infrared Properties And Empirical Relations From Wise., M. E. Cluver, T. H. Jarrett, A. M. Hopkins, S. P. Driver, J. Liske, M. L. P. Gunawardhana, E. N. Taylor, A. S. G. Robotham, M. Alpaslan, I. Baldry, M. J. I. Brown, J. A. Peacock, C. C. Popescu, R. J. Tuffs, A. E. Bauer, J. Bland-Hawthorn, M. Colless, Benne W. Holwerda, M. A. Lara-Lopez, K. Leschinski, A. R. Lopez-Sanchez, P. Norberg, M. S. Owers, L. Wang, S. M. Wilkins
Faculty and Staff Scholarship
The Galaxy And Mass Assembly (GAMA) survey furnishes a deep redshift catalog that, when combined with the Wide-field Infrared Survey Explorer (WISE), allows us to explore for the first time the mid-infrared properties of >110,000 galaxies over 120 deg2 to z 0.5. In this paper we detail the procedure for producing the matched GAMA-WISE catalog for the G12 and G15 fields, in particular characterizing and measuring resolved sources; the complete catalogs for all three GAMA equatorial fields will be made available through the GAMA public releases. The wealth of multiwavelength photometry and optical spectroscopy allows us to explore empirical relations …
The Ultraviolet Attenuation Law In Backlit Spiral Galaxies.,
2014
University of Alabama - Tuscaloosa
The Ultraviolet Attenuation Law In Backlit Spiral Galaxies., William C. Keel, Anna M. Manning, Benne W. Holwerda, Chris J. Lintott, Kevin Schawinski
Faculty and Staff Scholarship
The effective extinction law (attenuation behavior) in galaxies in the emitted ultraviolet (UV) regime is well known only for actively star-forming objects and combines effects of the grain properties, fine structure in the dust distribution, and relative distributions of stars and dust. We use Galaxy Evolution Explorer, XMM Optical Monitor, and Hubble Space Telescope (HST) data to explore the UV attenuation in the outer parts of spiral disks which are backlit by other UV-bright galaxies, starting with the candidate list of pairs provided by Galaxy Zoo participants. New optical images help to constrain the geometry and structure of the target …
Unveiling The Structure Of Barred Galaxies At 3.6 Μm With The Spitzer Survey Of Stellar Structure In Galaxies (S4g). I. Disk Breaks.,
2014
National Radio Astronomy Observatory
Unveiling The Structure Of Barred Galaxies At 3.6 Μm With The Spitzer Survey Of Stellar Structure In Galaxies (S4g). I. Disk Breaks., Taehyun Kim, Dimitri A. Gadotti, Kartik Sheth, E. Athanassoula, Albert Bosma, Myung Gyoon Lee, Barry F. Madore, Bruce G. Elmegreen, Johan H. Knapen, Dennis Zaritsky, Luis C. Ho, Sebastien Comeron, Benne W. Holwerda, Joannah L. Hinz, Juan Carlos Munoz-Mateos, Mauricio Cisternas, Santiago Erroz-Ferrer, Ron Buta, Eija Laurikainen, Heikki Salo, Jarkko Laine, Karin Menendez-Delmestre, Michael W. Regan, Bonita De Swardt, Armando Gil De Paz, Mark Seibert, Trisha Mizusawa
Faculty and Staff Scholarship
We have performed two-dimensional multicomponent decomposition of 144 local barred spiral galaxies using 3.6 μm images from the Spitzer Survey of Stellar Structure in Galaxies. Our model fit includes up to four components (bulge, disk, bar, and a point source) and, most importantly, takes into account disk breaks. We find that ignoring the disk break and using a single disk scale length in the model fit for Type II (down-bending) disk galaxies can lead to differences of 40% in the disk scale length, 10% in bulge-to-total luminosity ratio (B/T), and 25% in bar-to-total luminosity ratios. We find that for galaxies …
Arrakis : Atlas Of Resonance Rings As Known In The S4g.,
2014
University of Oulu
Arrakis : Atlas Of Resonance Rings As Known In The S4g., S. Comeron, H. Salo, E. Laurikainen, J. H. Knapen, R. J. Buta, M. Herrera-Endoqui, J. Laine, Benne W. Holwerda, K. Sheth, M. W. Regan, J. L. Hinz, J. C. Munoz-Mateos, A. Gil De Paz, K. Menendez-Delmestre, M. Seibert, T. Mizusawa, T. Kim, S. Erroz-Ferrer, D. A. Gadotti, E. Athanassoula, A. Bosma, L. C. Ho
Faculty and Staff Scholarship
Context. Resonance rings and pseudorings (here collectively called rings) are thought to be related to the gathering of material near dynamical resonances caused by non-axisymmetries in galaxy discs. This means that they are the result of secular evolution processes that redistribute material and angular momentum in discs. Studying them may give clues on the formation and growth of bars and other disc non-axisymmetries. Aims. Our aims are to produce a catalogue and an atlas of the rings detected in the Spitzer Survey of Stellar Structure in Galaxies (S4G) and to conduct a statistical study of the data in the catalogue. …
Determining Optical Constants With An Euv Polarimeter,
2014
Brigham Young University
Determining Optical Constants With An Euv Polarimeter, Fabian Walter, Dr. R. Steven Turley
Journal of Undergraduate Research
Characterizing mirrors is of great importance when designing optical devices. In order to control the reflectivity, these mirrors are made of multilayer structures. The index of refraction n, which allows for the calculation of the reflectivity, depends on the wavelength of the light. In the XUV (extreme ultraviolet) regime, n is not well known and experiments to determine it have to be done under vacuum due to the absorption of XUV light by air. This complicates the performing of experiments with light of that wavelength.
Characteristics Of An Infrared, Slitless, Spectroscopic, Emission-Line Galaxy Survey,
2014
Brigham Young University
Characteristics Of An Infrared, Slitless, Spectroscopic, Emission-Line Galaxy Survey, Jacob Peter Fugal, Dr. J. Ward Moody
Journal of Undergraduate Research
Cosmology has always attracted the minds of those who pursue the burning question of how the universe began. Since Edwin Hubble proved not only the existence of galaxies outside the Milky Way but also that the further away they are, the faster they are moving away, more and more research has given support to the “Big Bang” theory of the birth of the universe. This research includes the discovery of the cosmological microwave background radiation and the agreement of modeled and observed ratios of Hydrogen, Deuterium, Helium, and Lithium seen in primitive areas of galaxies.
The Inner Dynamical Mass Across Galaxy Morphology: A Weak Scaling With Total Stellar Mass,
2014
Case Western Reserve University
The Inner Dynamical Mass Across Galaxy Morphology: A Weak Scaling With Total Stellar Mass, Stacy S. Mcgaugh
Faculty Scholarship
We compile a sample of dispersion-supported and rotation-supported galaxies for which the dynamical mass enclosed at 500 pc can be measured. We find that this dynamical quantity increases only slowly with stellar mass (Mtotal(500 pc) ? M0.16 stars ) over ?9 decades in baryonic mass and ?3 in length scale, with a sudden upturn at the highest masses (Mstars - 1010 M-). This upturn occurs for the earliest types (S0 and Sa) of disk galaxies, and is consistent with the extra mass within 500 pc being predominantly stellar. This sudden change may be indicative of different bulge formation mechanisms between …
Deposition And Analysis Of Copper Indium Disulfide For Photovoltaic Applications,
2014
Macalester College
Deposition And Analysis Of Copper Indium Disulfide For Photovoltaic Applications, Frederick Wade
Macalester Journal of Physics and Astronomy
Thin Film semiconductors were created through the methods of electrochemistry to produce a copper, indium and sulfur metal alloy that could be placed on a stainless steel substrate. We observed other properties regarding the relative indium to copper relationships and both the macro and micro structure of the final product. X-‐ray diffraction, SEM imaging, and atomic absorption spectroscopy data suggest a relatively intact metal alloy, but also an inaccurate ratio of indium to copper.
Photometric And Spectroscopic Analysis Of Young, Nearby Open Cluster Collinder 70,
2014
Macalester College
Photometric And Spectroscopic Analysis Of Young, Nearby Open Cluster Collinder 70, Clara M. Thomann
Macalester Journal of Physics and Astronomy
We present the results of a wide-field (80’ x 80’) photometric and spectroscopic survey of the young open cluster Collinder 70, which is also known as the ORI OB 1b association, centered on the central star of Orion’s belt, ε Ori (Alnilam). Seventy Coll 70 spectroscopy targets were selected from BVRIc color magnitude diagrams for observation using the CTIO HYDRA multi-object spectrograph; we aimed to identify targets exhibiting H" in emission and a strong lithium 6708Å line in absorption. About a third of our targets (23/70 stars) are consistent with being youthful members of Coll 70. Intermediate resolution (R!20000) HYDRA …
Monte Carlo Simulation For Silicon On Silane Hwcvd For Thin Film Solar Cells,
2014
Macalester College
Monte Carlo Simulation For Silicon On Silane Hwcvd For Thin Film Solar Cells, Annaleigh Smith
Macalester Journal of Physics and Astronomy
Thin film solar cells offer a viable alternative to crystal silicon solar cells. They are expected to be cheaper to fabricate because they use material more efficiently, and are deposited in a process which can create larger area solar cells [1]. However, a high deposition rate is necessary for economic viability. A Monte Carlo simulation can model the molecular interactions in hot wire chemical vapor deposition and track the position and velocity distribution of molecular species in the gas [2]. Determining the flux on the substrate can help us to increase deposition rate by adjusting control parameters accordingly [3]. As …
Galaxy Merger Identification In The Goods-South Field,
2014
Macalester College
Galaxy Merger Identification In The Goods-South Field, Erin O'Leary
Macalester Journal of Physics and Astronomy
We analyzed a catalog of 7,628 galaxies at 0 < z < 4 from CANDELS1 in the GOODS-South2 field in order to identify a sample of galaxy mergers and interactions. Galaxy mergers are believed to play a fundamental role in galaxy evolution. Developing methods to robustly and efficiently identify mergers becomes vital with our increasing ability to study mergers at higher redshifts and in larger samples. We explored merger identification based on visual morphology classification and preliminary attempts with automated quantitative methods. Using multiple detailed visual morphology classifications for each galaxy conducted by the CANDELS structure and morphology team, we created selection criteria to …
Shield: Star Formation From Wiyn And Galex Imaging,
2014
Macalester College
Shield: Star Formation From Wiyn And Galex Imaging, Samilee J. Moody
Macalester Journal of Physics and Astronomy
Using images from the GALEX (Galaxy Evolution Explorer) GR6 pipeline (released 2010), as well as the WIYN 3.5m Observatory, we present a survey of the twelve SHIELD galaxies in the far-ultraviolet (FUV, 1500 Å) and near-ultraviolet (NUV, 2200 Å) filters. FUV data were available for eleven of the galaxies, AGC 749237 being the exception. Aperture photometry was performed on each image to determine the AB magnitude in the FUV and NUV filters.These values were then used to calculate flux, luminosity, and star formation rates (SFRs). Similarly, Hα images of each galaxy from WIYN (omitting AGC 749241) were analyzed to determine …
Numerical Modeling Of The Finite Well With Implications For Observing Quantum Interference Between Coherent Electron Wave,
2014
Macalester College
Numerical Modeling Of The Finite Well With Implications For Observing Quantum Interference Between Coherent Electron Wave, Jacob M. Moen
Macalester Journal of Physics and Astronomy
We use numerical modeling in Fortran to investigate the claims of Wollenhaupt et al. (2006) and Hommelhoff et al. (2002) regarding ultra-short electron pulses ionized via laser excitation of a tungsten nanotip. We assume that the nanotip acts as a finite one‐dimensional potential well with the depth equal to the work function of tungsten and the width of the order of the radius of curvature of the nanotip. The interactions of propagating Gaussian wave packets are modeled in order to give insight into the temporal and spatial evolution of the generated electron wave packets. Furthermore we hope to demonstrate the …
