Bulletin of the American Physical Society
Joint Spring 2012 Meeting of the Texas Sections of the APS and AAPT and Zone 13 of the SPS
Volume 57, Number 2
Thursday–Saturday, March 22–24, 2012; San Angelo, Texas
Session C1: Contributed Oral Presentations: APS 1 |
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Chair: Wayne Keith, McMurry University Room: Houston Harte University Center UC 203 |
Friday, March 23, 2012 10:30AM - 10:42AM |
C1.00001: Comparing the Bruntz et al. (2012) viscous potential formula to the ionospheric cross-polar cap potential from two empirical formulas Robert Bruntz, Cezanne Narcisse, Joseph Schinco, Kyle Van Zuiden, Ramon Lopez As the solar wind flows past the Earth, it interacts by two main methods: magnetic reconnection between the interplanetary magnetic field (IMF) and the Earth's magnetic field; and a viscous interaction between the solar wind plasma and plasma trapped in Earth's magnetic field. Both interactions produce electrical fields, and thus electrical potentials, in Earth's ionosphere. The Bruntz et al. (2012) viscous potential formula was derived from studies of the viscous interaction in the Lyon-Fedder-Mobarry (LFM) magnetohydrodynamic (MHD) simulation, to predict the ionospheric electrical potential resulting from the viscous interaction. Recent results have shown that the viscous interaction is constant for southward IMF values, but is reduced for northward IMF. We will compare the Bruntz et al. (2012) formula (which is insensitive to IMF values) to the output of the Weimer (2005) empirical model and the Assimilative Mapping of Ionospheric Electrodynamics (AMIE) model, to see whether those results also reduce the viscous interaction when the IMF is northward. [Preview Abstract] |
Friday, March 23, 2012 10:42AM - 10:54AM |
C1.00002: Small Telescope Exoplanet Transit Search (STExTS) Transit Candidates in the Open Cluster Dolidze-Dzimsevijli 9 (DD9) Blaise DuFrain, Richard Olenick, Arthur Sweeney, Andrew Bechter, Eric Bechter The STExTs project searched for transit candidates in the open cluster Dolidze-Dzimselshvili 9 in Hercules for 37 nights using a f/2.8 152 mm astrograph. Approximately 11,000 images were obtained, processed, and analyzed for signatures of transits. We will present preliminary candidates and orbital periods. [Preview Abstract] |
Friday, March 23, 2012 10:54AM - 11:06AM |
C1.00003: The stability of the suggested planet in the $\nu $ Octantis system: a numerical and statistical study Billy Quarles, Manfred Cuntz, Zdzislaw Musielak Exoplanets in binary systems have received heightened interest by the scientific community. Especially with the recent detection of a circumbinary planet of Kepler-16b (Doyle et al. 2011)[Science 333, 1602] planets in binary systems have warranted second and even third glances. The system of $\nu $ Octantis has been a system of great controversy since the suggested planet in this system (Ramm et al. 2009)[MNRAS 394, 1695] appears to be located beyond its theoretical stability limit. In order to resolve this controversy we seek to determine whether the proposed planet can exist in the context of current stability theory. We have performed detailed simulations by exploiting the uncertainty measurements to determine the short and long-term stability of a prograde starting configuration. However to follow up on the previous results by Eberle {\&} Cuntz (2010)[ApJ 721, L168], we have investigated the hypothesis of a retrograde orbit in more detail by considering a larger set of possible initial conditions to determine the possibility of a retrograde configuration with respect to the motion of the binary system. We will show that a retrograde configuration is preferred by both stability considerations with respect to the maximum Lyapunov exponent and numerical statistical considerations. [Preview Abstract] |
Friday, March 23, 2012 11:06AM - 11:18AM |
C1.00004: Toward Two-dimensional Velocity Fields in Kiloparsec-scale Quasar Jets David Hough, Gareth Jones An outstanding question in quasar jet physics concerns their velocity fields (Blandford 2008, ASP Conf.Ser. 386, 3). We are investigating this in a sample of 21 3CR lobe-dominated quasars. Complex structures and narrow widths present difficulties not found in smooth, well-resolved radio galaxy jets (Laing and Bridle 2002, MNRAS, 336, 328). We now have a systematic method for distinguishing between compact knots and lower-level inter-knot emission. Application to four sources with prominent knot trains in Bridle et al. (1994, AJ, 108, 766) shows that the first knot is the brightest with a simple Gaussian profile. Succeeding knots are both fainter and have a broad, complex base of associated emission. We will report on analyses of knot vs. inter-knot brightnesses and their implications via Doppler boosting for longitudinal velocity fields. We have also begun investigating transverse velocity fields by convolving trial spine-sheath profiles with the beam. We studied profiles with a fast spine occupying the central one-third, Doppler-dimmed by a factor of two relative to a slower sheath, with these results: a spine of width half a beam yields a convolved profile 30 per cent wider than the beam, while a spine of width one beam leads to a clearly resolved sheath. [Preview Abstract] |
Friday, March 23, 2012 11:18AM - 11:30AM |
C1.00005: Photometric Search for Variables in DD9 with STExTS Eric Bechter, Richard Olenick, Arthur Sweeney, Blaise DuFrain, Andrew Bechter The Small Telescope Extrasolar Transit Searches (STExTS) project is a small aperture, wide-angle search for planetary transits and variable stars. Observations of the open cluster Dolidze-Dzimseleshvili 9 were made with an f/2.8 152 mm astrograph for 37 nights in 2011. Lightcurves were obtained for approximately 1900 stars that were extracted and catalogued from the images. We report on preliminary results and characteristics of new binary stars discovered. [Preview Abstract] |
Friday, March 23, 2012 11:30AM - 11:42AM |
C1.00006: Automation of the Telescope in the Observatory at Texas State University-San Marcos Cary Smith The telescope in the Observatory at Texas State University - San Marcos is automated by means of off the shelf parts with a budget of {\$}300.00. This telescope retrofit is to replace obsolete and malfunctioning hardware and update software. The telescope upgrade entailed the removal of all of the timeworn hardware and thorough testing of the motors and encoders to insure proper functionality. From a less expensive telescope a new motor control board is acquired that is capable of performing tasks beyond the capabilities of the old board. A Schmitt Trigger and a set of four capacitors in series are used to lessen the noise produced by the older model motors and encoders. All of the retrofitted hardware is tested to insure proper functionality for the final product before installation into the telescope. After final installation a problem with the communication between software and hardware was found and remedied. [Preview Abstract] |
Friday, March 23, 2012 11:42AM - 11:54AM |
C1.00007: Increasing Astronomical Photographic Resolution by Convolution Matrices Gerard Nickel In digital astronomical image processing, distortion limits the quality of photometric data. Often, this precludes accurate and precise analysis of stars or planetary features imaged close to one another. This is a problem in particular for period analysis of binary stars and searching for planetary transits, due to the merging of nearby stars into the area of interest. I proposed a method which utilizes a pair of filters and pixel math to increase resolution, thereby improving astronomical image features and enabling more precise analysis thereof. Comparison of processed and unprocessed data was done by comparing signal to noise ratio and brightness profiles of each. All calculations were performed and results analyzed using Astronomical Image Processing for Windows (AIP4WIN) by Richard Berry. In many cases, previously unusable star profiles were resolved sufficiently to take photometric data from them, while those with low signal to noise ratios improved by a factor of two to three. These results suggest that the proposed method could be used to enable photometric analysis of previously un-usable data. [Preview Abstract] |
Friday, March 23, 2012 11:54AM - 12:06PM |
C1.00008: Analysis of Beam Test Data from UTA GEM Prototype Chambers with One-Bit Digital Readout System Danrae Pray Gas Electron Multiplier (GEM) technology is currently a strong candidate for a Digital Hadron Calorimeter to be implemented in an experiment in future accelerators such as the International Linear Collider. The University of Texas at Arlington High Energy Physics Group has been developing prototype GEM detectors which contain two layers of GEM foils. The team performed a two week long beam test of four prototype chambers with dimensions 30cm by 30cm at Fermi National Accelerator Laboratory in August of 2011. Three of these chambers were equipped with the one bit DCAL chip readout system jointly developed by Argonne National Laboratory and Fermi National Accelerator Laboratory teams. In this talk, we give an updated report of the results of the test beam data analysis of the GEM prototype detector functionality, responses to various particle types, efficiency dependence on threshold and high voltage, as well as the current/future studies that the UTA team is performing with the GEM detectors and DCAL readout system. [Preview Abstract] |
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