Astrophysics and Astronomy Commons^™

Session B-5: Planetary Science And The Ngss, Eric Hawker

Professional Learning Day

The goal of this session is to use what we understand about other planets and moons in our Solar System in order to get a better understanding of the Earth.

Star Formation And Substructure In Galaxy Clusters, Seth A. Cohen, Ryan C. Hickox, Gary A. Wegner, Maret Einasto, Jaan Vennik

Dartmouth Scholarship

We investigate the relationship between star formation (SF) and substructure in a sample of 107 nearby galaxy clusters using data from the Sloan Digital Sky Survey (SDSS). Several past studies of individual galaxy clusters have suggested that cluster mergers enhance cluster SF, while others find no such relationship. The SF fraction in multi-component clusters (0.228 +/- 0.007) is higher than that in single-component clusters (0.175 +/- 0.016) for galaxies with M^0.1_r < -20.5. In both single- and multi-component clusters, the fraction of star-forming galaxies increases with clustercentric distance and decreases with local galaxy number density, and multi-component clusters show a higher SF fraction than single-component clusters at almost all clustercentric distances and local densities. Comparing the SF fraction in individual clusters to several statistical measures of substructure, we find weak, but in most cases significant at greater than 2 sigma, correlations between substructure and SF fraction. These results could indicate that cluster mergers may cause weak but significant SF enhancement in clusters, or unrelaxed clusters exhibit slightly stronger SF due to their less evolved states relative to relaxed clusters.

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, Trisha Mizusawa

Aerospace, Physics, and Space Science Faculty Publications

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 …

Utah Valley Air Sample Measurements, Ryan Hamilton, Dr. Lawrenece Rees, Dr. Nolan Mangelson, Dr. Delbert Eatough

Journal of Undergraduate Research

In an effort at reducing the carbon monoxide levels in the atmosphere, Utah has mandated the use of oxygenated fuels during winter inversions. While the fuel additive has been shown to reduce CO levels by as much as 4%, the unique chemistry of the air in Utah Valley has raised concerns about the oxygenated fuels contributing to air pollution in the form of fine particulate matter–a pollutant recently brought under tighter regulation by the EPA. To diagnose the problem, air samples from around Utah Valley were taken during the winter, both in times of inversion and in times when there …

A Comparison Of Y Scuti And Y Doradus Variable Stars, Matthew B. Garvin, Dr. Eric Hintz

Journal of Undergraduate Research

During the course of this summer, I observed a possible ã Doradus/ä Scuti variable star, V927 Herculis. Observations of this star were made using the David Derrick 16 inch telescope located on the Brigham Young University (BYU) campus in the Orson Pratt Observatory. Due to the often inclement weather, five nights of time-series photometry data were obtained. The data were compared to the known characteristics of the ä Scuti and ã Doradus class of variable stars. V927 Herculis was found to have characteristics similar to both classes. Spectroscopic data need to be obtained to make a clear distinction of which …

Secular Damping Of Stellar Bars In Spinning Dark Matter Halos, Stacy Long, Isaac Shlosman, Clayton Heller

Physics and Astronomy Faculty Publications

We demonstrate using numerical simulations of isolated galaxies that growth of stellar bars in spinning dark matter halos is heavily suppressed in the secular phase of evolution. In a representative set of models, we show that for values of the cosmological spin parameter λ ≳ 0.03, bar growth (in strength and size) becomes increasingly quenched. Furthermore, the slowdown of the bar pattern speed weakens considerably with increasing λ until it ceases completely. The terminal structure of the bars is affected as well, including extent and shape of their boxy/peanut bulges. The essence of this effect lies in the modified angular …

Secular Damping Of Stellar Bars In Spinning Dark Matter Halos, Stacy Long, Isaac Shlosman, Clayton Heller

Physics & Astronomy: Faculty Publications

We demonstrate using numerical simulations of isolated galaxies that growth of stellar bars in spinning dark matter halos is heavily suppressed in the secular phase of evolution. In a representative set of models, we show that for values of the cosmological spin parameter λ ≳ 0.03, bar growth (in strength and size) becomes increasingly quenched. Furthermore, the slowdown of the bar pattern speed weakens considerably with increasing λ until it ceases completely. The terminal structure of the bars is affected as well, including extent and shape of their boxy/peanut bulges. The essence of this effect lies in the modified angular …

Minisuperspace Canonical Quantization Of The Reissner-Nordström Black Hole Via Conditional Symmetries, T. Christodoulakis, Nicholas Dimakis, Petros A. Terzis, Babak Vakili, E. Melas, Th. Grammenos

Physics & Astronomy Faculty Publications

We use the conditional symmetry approach to study the r evolution of a minisuperspace spherically symmetric model both at the classical and the quantum level. After integration of the coordinates t, θ and ϕ in the gravitational plus electromagnetic action the configuration space dependent dynamical variables turn out to correspond to the r-dependent metric functions and the electrostatic field. In the context of the formalism for constrained systems (Dirac-Bergmann, Arnowitt-Deser-Misner) with respect to the radial coordinate r, we set up a pointlike reparametrization invariant Lagrangian. It is seen that, in the constant potential parametrization of the lapse, the corresponding minisuperspace …

Spot Activity Of The Rs Canum Venaticorum Star Σ Geminorum, Perttu Kajatkari, Thomas Hackman, Lauri Jetsu, Jyri J. Lehtinen, Gregory W. Henry

Information Systems and Engineering Management Research Publications

Aims. We model the photometry of RS CVn star σ Geminorum to obtain new information on the changes of the surface starspot distribution, that is, activity cycles, differential rotation, and active longitudes.

Methods. We used the previously published continuous period search (CPS) method to analyse V-band differential photometry obtained between the years 1987 and 2010 with the T3 0.4 m Automated Telescope at the Fairborn Observatory. The CPS method divides data into short subsets and then models the light-curves with Fourier-models of variable orders and provides estimates of the mean magnitude, amplitude, period, and light-curve minima. These light-curve parameters …

Preventing Asteroid Impact By Deflection: A Numerical Simulation, Rebecca J. Carlson

Journal of Undergraduate Research

Small objects from outer space collide with the earth’s atmosphere every day. Most of these are small enough to burn up completely before hitting the ground. A few, however, reach the earth’s surface as meteorites. On occasion, an asteroid large enough to cause serious darnage impacts the earth. Although impacts large enough to destroy cities only occur once in a thousand years or so, if such an event were to occur there would be great loss of life and damage of property (Rather 1992). Because of this, it is important to develop plans to deter an asteroid on a colllslon …

Pioneer Venus Orbiter Retarding Potential Analyzer Observations Of The Electron Component Of The Solar Wind And Observations Of Venus Bow Shock Crossings And The Magnetosheath Region, Noe Yamaguchi

Journal of Undergraduate Research

A bow shock is a paraboloid-shaped shockwave that forms around a planet similar to one that forms around an airplane traveling faster than the speed of sound. We may observe this shock by the change in plasma parameters before and after entering the bow shock. Those plasma parameters include temperature, density, pressure, velocity, magnetic field and others.

Tracing The Evolution Of Active Galactic Nuclei Host Galaxies Over The Last 9 Gyr Of Cosmic Time, A. D. Goulding, W. R. Forman, R. C. Hickox, C. Jones

Dartmouth Scholarship

We present the results of a combined galaxy population analysis for the host galaxies of active galactic nuclei (AGN) identified at 0 < z < 1.4 within the Sloan Digital Sky Survey, Boötes, and DEEP2 surveys. We identified AGN in a uniform and unbiased manner at X-ray, infrared, and radio wavelengths. Supermassive black holes undergoing radiatively efficient accretion (detected as X-ray and/or infrared AGN) appear to be hosted in a separate and distinct galaxy population than AGN undergoing powerful mechanically dominated accretion (radio AGN). Consistent with some previous studies, radiatively efficient AGN appear to be preferentially hosted in modest star-forming galaxies, with little dependence on AGN or galaxy luminosity. AGN exhibiting radio-emitting jets due to mechanically dominated accretion are almost exclusively observed in massive, passive galaxies. Crucially, we now provide strong evidence that the observed host-galaxy trends are independent of redshift. In particular, these different accretion-mode AGN have remained as separate galaxy populations throughout the last 9 Gyr. Furthermore, it appears that galaxies hosting AGN have evolved along the same path as galaxies that are not hosting AGN with little evidence for distinctly separate evolution.

First Searches For Optical Counterparts To Gravitational-Wave Candidate Events, M. Constancio, J. Aasi, J. Abadie, B. P. Abbott, Teviet Creighton, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, Malik Rakhmanov, Joseph D. Romano

Physics & Astronomy Faculty Publications

During the Laser Interferometer Gravitational-wave Observatory and Virgo joint science runs in 2009-2010, gravitational wave (GW) data from three interferometer detectors were analyzed within minutes to select GW candidate events and infer their apparent sky positions. Target coordinates were transmitted to several telescopes for follow-up observations aimed at the detection of an associated optical transient. Images were obtained for eight such GW candidates. We present the methods used to analyze the image data as well as the transient search results. No optical transient was identified with a convincing association with any of these candidates, and none of the GW triggers …

First Searches For Optical Counterparts To Gravitational-Wave Candidate Events, Tiffany Summerscales, Ligo Scientific Collaboration And Virgo Collaboration

Faculty Publications

During the Laser Interferometer Gravitational-wave Observatory and Virgo joint science runs in 2009-2010, gravitational wave (GW) data from three interferometer detectors were analyzed within minutes to select GW candidate events and infer their apparent sky positions. Target coordinates were transmitted to several telescopes for follow-up observations aimed at the detection of an associated optical transient. Images were obtained for eight such GW candidates. We present the methods used to analyze the image data as well as the transient search results. No optical transient was identified with a convincing association with any of these candidates, and none of the GW triggers …

Welcome And Opening Remarks, Rick C. Chappell

Magnetospheric-Ionospheric Coupling Conference

No abstract provided.

A Three-Year Multi-Wavelength Study Of The Very-High-Energy Gamma-Ray Blazar 1es 0229+200, P. T. Reynolds, Et. Al.

Physical Sciences Publications

The high-frequency-peaked BL Lacertae object 1ES 0229+200 is a relatively distant (z = 0.1396), hard-spectrum (Γ ~ 2.5), very-high-energy (VHE; E > 100 GeV) emitting γ-ray blazar. VHE measurements of this active galactic nucleus have been used to place constraints on the intensity of the extragalactic background light and the intergalactic magnetic field (IGMF). A multi-wavelength study of this object centered around VHE observations by Very Energetic Radiation Imaging Telescope Array System (VERITAS) is presented. This study obtained, over a period of three years, an 11.7 standard deviation detection and an average integral flux F(E > 300 GeV) = (23.3 ± 2.8stat …

Study Of The Eclipsing Binary Ah Cancri, Delora Chere' Tanner, Dr. Benjamin Taylor

Journal of Undergraduate Research

Unlike research in many other disciplines, astronomical research is highly dependent upon the weather. My original proposed research was to further the task of calibrating standard stars in the M67 open cluster. Unfortunately the weather was unfavorable during the window of time that this cluster was available for viewing, therefore, I could not secure the amount of data needed to conduct my proposed research. I decided to change the focus of my research to an individual star located in M67, AH Cancri. I was able to use raw archive data of the M67 star field to study this star.

Scalar Waves Scattering Off A Cylinder, David Oliphant, Dr. R. Steven Turley

Journal of Undergraduate Research

Scattering problems are common in physics. A scattered (reflected) wave or particle from an object can give us hints to the nature of the object’s shape, size, color, or composition. This is the basic principle behind sonar, radar, ultrasound, NMR, and even vision. One technique in determining the nature of a scattered wave is called the Method of Moments. It involves solving the Helmholtz equation by representing the object’s response or current as a sum of basis functions and weights. The number of basis functions used is important. If there are too many the computational time becomes inordinate. However, there …

Extreme Ultraviolet Ellipsometry, Spencer E. Olson, Dr. R. Steven Turley

Journal of Undergraduate Research

Ellipsometry, a common technique used with visible light, measures the change of the state of polarization as it reflect off a material. By so doing, the way that light interacts with materials can be understood more clearly. Also, optical properties, known as the index of refraction and absorption coefficient, can be found from this technique. With these known optical properties of various materials, elements, such as mirrors and polarizers, can be optimized for optical instruments. The name ellipsometry comes from the fact that the technique is based on the analysis of what is called ellipsometrically polarized light. For the simple …

Semiclassical Quantization: Corrections And Causes, Teresa Griffin

Journal of Undergraduate Research

My research over the past six months has produced a method of understanding the differences between semiclassical approximation methods and the exact quantum results.

Work Towards Building An Extreme Ultraviolet Ellipsometer, Cort N. Johnson, Dr. David D. Allred

Journal of Undergraduate Research

The extreme ultraviolet (EUV) optics group at Brigham Young University uses thin film technology to develop multiplayer mirrors and designed to reflect well at certain EUV wavelengths. We need methods of measuring layer thickness on the order of a few angstroms. One method often used in thin film sample analysis is ellipsometry.

Interaction Between The Broad-Lined Type Ic Supernova 2012ap And Carriers Of Diffuse Interstellar Bands, Dan Milisavljevic, Raffaella Margutti, Kyle N. Crabtree, Jonathan B. Foster, Alicia M. Soderberg, Robert A. Fesen, Jerod T. Parrent

Dartmouth Scholarship

Diffuse interstellar bands (DIBs) are absorption features observed in optical and near-infrared spectra that are thought to be associated with carbon-rich polyatomic molecules in interstellar gas. However, because the central wavelengths of these bands do not correspond to electronic transitions of any known atomic or molecular species, their nature has remained uncertain since their discovery almost a century ago. Here we report on unusually strong DIBs in optical spectra of the broad-lined Type Ic supernova SN 2012ap that exhibit changes in equivalent width over short ( 30 days) timescales. The 4428 Å and 6283 Å DIB features get weaker with …

Two-Neutron Transfer Reaction Mechanisms In 12C(6He, 4He) 14C Using A Realistic Three-Body 6He Model, D. Smalley, F. Sarazin, F. M. Nunes, B. A. Brown, P. Adsley, H. Al-Falou, C. Andreoiu, B. Baartman, G. C. Ball, J. C. Blackmon, H. C. Boston, W. N. Catford, S. Chagnon-Lessard, A. Chester, R. M. Churchman, D. S. Cross, C. Aa. Diget, D. Di Valentino, S. P. Fox, B. R. Fulton, A. Garnsworthy, G. Hackman, U. Hager, R. Kshetri, J. N. Orce, N. A. Orr, E. Paul, M. Pearson, E. T. Rand, J. Rees, S. Sjue, C. E. Svensson, E. Tardiff, A. Diaz Varela, S. J. Williams, Steven W. Yates

Physics and Astronomy Faculty Publications

The reaction mechanisms of the two-neutron transfer reaction ¹²C(⁶He,⁴He) have been studied at E_lab=30 MeV at the TRIUMF ISAC-II facility using the Silicon Highly-segmented Array for Reactions and Coulex (SHARC) charged-particle detector array. Optical potential parameters have been extracted from the analysis of the elastic scattering angular distribution. The new potential has been applied to the study of the transfer angular distribution to the 2+₂ 8.32 MeV state in ¹⁴C, using a realistic three-body ⁶He model and advanced shell-model calculations for the carbon structure, allowing to calculate the relative contributions …

The Orbits Of The Triple-Star System 1 Geminorum From Phases Differential Astrometry And Spectroscopy, Benjamin F. Lane, Matthew W. Muterspaugh, Roger F. Griffin, Colin D. Scarfe, Francis C. Fekel, Michael H. Williamson, Joel A. Eaton, Michael Shao, Mark M. Colavita, Maciej Konacki

Information Systems and Engineering Management Research Publications

We have used precise differential astrometry from the Palomar High-precision Astrometric Search for Exoplanet Systems project and radial-velocity measurements covering a time span of 40 yr to determine the orbital parameters of the 1 Geminorum triple system. We present the first detection of the spectral lines of the third component of the system, together with precise mass (0.5%) and distance (0.15%) determinations for this system. In addition, our astrometry allows us to make the first determination of the mutual inclination of the orbits.

The Spacetime Geometry Of A Null Electromagnetic Field, Charles G. Torre

Presentations and Publications

We give a set of local geometric conditions on a spacetime metric which are necessary and sufficient for it to be a null electrovacuum, that is, the metric is part of a solution to the Einstein–Maxwell equations with a null electromagnetic field. These conditions are restrictions on a null congruence canonically constructed from the spacetime metric, and can involve up to five derivatives of the metric. The null electrovacuum conditions are counterparts of the Rainich conditions, which geometrically characterize non-null electrovacua. Given a spacetime satisfying the conditions for a null electrovacuum, a straightforward procedure builds the null electromagnetic field from …

Kelt-6b: A P ~ 7.9 Day Hot Saturn Transiting A Metal-Poor Star With A Long-Period Companion, K. A. Collins, J. D. Eastman, T. G. Beatty, R. J. Siverd, B. S. Gaudi, J. Pepper, J. F. Kielkopf, J. A. Johnson, A. W. Howard, D. A. Fischer, M. Manner, A. Bieryla, D. W. Latham, B. J. Fulton, J. Gregorio, L. A. Buchhave, Eric L.N. Jensen, K. G. Stassun, K. Penev, J. R. Crepp, S. Hinkley, R. A. Street, P. Cargile, C. E. Mack, T. E. Oberst, R. L. Avril, S. N. Mellon, K. K. Mcleod, M. T. Penny, R. P. Stefanik, P. Berlind, M. L. Calkins, Q. Mao, A. J.W. Richert, D. L. Depoy, G. A. Esquerdo, A. Gould, J. L. Marshall, R. J. Oelkers, R. W. Pogge, M. Trueblood, P. Trueblood

Physics & Astronomy Faculty Works

We report the discovery of KELT-6b, a mildly inflated Saturn-mass planet transiting a metal-poor host. The initial transit signal was identified in KELT-North survey data, and the planetary nature of the occulter was established using a combination of follow-up photometry, high-resolution imaging, high-resolution spectroscopy, and precise radial velocity measurements. The fiducial model from a global analysis including constraints from isochrones indicates that the V = 10.38 host star (BD+31 2447) is a mildly evolved, late-F star with T _eff = 6102 ± 43 K, log g_\star =4.07_{-0.07}^{+0.04}, and [Fe/H] = -0.28 ± 0.04, with an inferred mass M _sstarf = …

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., 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 …

Interaction Of Magnetic Reconnection And Kelvin-Helmholtz Modes For Large Magnetic Shear: 1. Kelvin-Helmholtz Trigger, Xuanye Ma, Antonius Otto, Peter A. Delamere

Publications

At the Earth's magnetopause, both magnetic reconnection and the Kelvin‐Helmholtz (KH) instability can operate simultaneously for southward interplanetary magnetic field conditions. The dynamic evolution of such a system can be expected to depend on the importance of KH wave evolution versus reconnection and therefore on the respective initial perturbations. In this study, a series of local three‐dimensional MHD and Hall MHD simulations are carried out to investigate the situation where the Kelvin‐Helmholtz instability is initially the primary process. It is demonstrated that magnetic reconnection is driven and strongly modified by nonlinear KH waves. The highest reconnection rate is close to …

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 …