Bulletin of the American Physical Society
2006 Texas Section of the APS Joint Fall Meeting
Thursday–Saturday, October 5–7, 2006; Arlington, Texas
Session AP2: Astrophysics II |
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Chair: David Hough, Trinity University Room: UT Arlington, University Center Red River |
Saturday, October 7, 2006 10:30AM - 10:42AM |
AP2.00001: Near-Infrared Properties of Luminous Blue Galaxies M. McDermott, M. Fanelli In an effort to better understand galactic evolution, we present an investigation into the star formation history of luminous blue galaxies using near-infrared photometry in the J (1.3$\mu )$, H (1.8$\mu )$, and K$_{s}$ (2.2$\mu )$ bands. A sample of 154 Markarian galaxies was selected based on strong recent star formation rates (SFR) greater than 10 solar masses per year, as indicated by observed thermal infrared emission from the Infrared Astronomical Survey (IRAS). Near-infrared magnitudes and colors were obtained from the 2 Micron All-Sky Survey (2MASS), which observed the entire sky in these bands. These relatively nearby galaxies are unusual in that they exhibit SFR more typical of galaxies observed early in cosmic time. Near-infrared light is emitted primarily by cool stars (G, K, or M spectral types), with most of the light provided by the old stellar component in these galaxies. Investigating these infrared colors using color-color diagrams provides insight into the nature and total mass of the underlying galaxy and helps constrain the starburst strength and duration. [Preview Abstract] |
Saturday, October 7, 2006 10:42AM - 10:54AM |
AP2.00002: gpb, the Damocles sword hanging over GR. Russell Collins The gpb experiment is now testing the GR concept of curved space. A gyroscope, orbiting earth in low polar orbit, should precess in the direction of earth's spin because of spin-orbit coupling. If this tiny precession of 43 masec/yr is found, it will favor GR. Failure to find this precession will doom GR and all other metric theories of gravity. Space itself will be found, experimentally, to be flat. My interest arises from mass-metric relativity (1), a scalar theory of gravity in flat space. In MMR, mass is not a constant. Gravity and speed increase mass, and quantum mechanics tells us that meter sticks will shrink. In MMR, it is not space that is distorted but rather it is our measuring instruments. Space remains Euclidean, and Newtonian gravity works fine. MMR accounts equally well with GR for the classical tests of GR, but differs in its predictions for the gpb. Instead of +43 masec/yr, MMR predicts -19 masec/yr. There is no spin-orbit coupling, but the geodetic perturbation of the sun causes a backward precession. The Stanford gpb has flown, the data has been collected, and the analysis is nearly complete and is scheduled for announcement next April. Much of physics may need revision. (1) Collins, R.L., arXiv 0012059 (2000). [Preview Abstract] |
Saturday, October 7, 2006 10:54AM - 11:06AM |
AP2.00003: Effects of Temperature Gradients on Transverse Oscillations of Solar Magnetic Flux Tubes Shilpa Subramaniam, Zdzislaw Musielak, Reiner Hammer Propagation of transverse waves along thin magnetic flux tubes embedded in an isothermal atmosphere is affected by the cutoff frequency, which is a global quantity that restricts the wave propagation to only those frequencies that are higher than the cutoff. The tubes respond to freely propagating waves by oscillating at the cutoff frequency. Since the solar atmosphere is not isothermal, the effects of different temperature gradients on the cutoff are investigated. It is shown that the cutoff frequency in a non-isothermal atmosphere becomes a local quantity and its physical meaning is different than the global cutoff. The obtained results are used to explain the observed frequencies of oscillations of solar magnetic flux tubes. [Preview Abstract] |
Saturday, October 7, 2006 11:06AM - 11:18AM |
AP2.00004: Numerical Exploration of an Integrable Analog to a One-Dimensional Gravitating System Kenneth Yawn, Bruce Miller The first gravitational simulations employed a one dimensional gravitational sheet system (OGS) consisting of N parallel mass sheets that interact purely through the gravitational force. Numerous studies have shown this system to have characteristics in common with the famous Fermi-Pasta-Ulam problem in that it resists relaxation to equilibrium. As a result, it is of special interest in the study of non-linear dynamics and of the thermodynamics of systems with long range interactions. Exchange symmetry in acceleration partitions the configuration space of an N particle OGS into N! equivalent cells. As a consequence of the small angular separation of the acceleration in neighboring cells, an exactly integrable system (EIS) can be constructed that takes the form of a central force problem in N-1 dimensions. Numerical experiments have been performed on this integrable system analogous to the OGS. These experiments are employed to compare the time evolution of the EIS and the OGS. Under some special circumstances we find excellent agreement with theory. [Preview Abstract] |
Saturday, October 7, 2006 11:18AM - 11:30AM |
AP2.00005: Supernovae in Luminous Blue Galaxies Cassidy Smith, Mike Fanelli Data from the Katzman Automatic Imaging Telescope was used to find angular and physical separations between supernovae and their host galaxies. The goal was to find a distribution in host galaxies that SN are being found in. A tabulation was also made on which morphology types produce the most amount of SN. The supernova rate in some Blue Compact Galaxies were found by using the star formation rate, then their approximate sizes were figured using the Sloan Digital Sky Survey. We used NED, NARO, and FIRST to find radio fluxes for the same BCGs to go back in later and compare them with the combined thermal and non-thermal emission. [Preview Abstract] |
Saturday, October 7, 2006 11:30AM - 11:42AM |
AP2.00006: Detecting Globular Star Cluster Tidal Streams William Lee Powell Jr., Ronald Wilhelm, Adam Lauchner, Andrew McWilliam Globular cluster tidal streams are of interest for what they can tell us of the dynamical evolution of the clusters and of our Galaxy. Recent studies have used photometric and statistical subtraction methods to attempt to separate potential streams from the field stars that contaminate the samples. As our primary method we choose instead to use photometry to select blue stars that match the horizontal branch of the clusters. We then make spectroscopic observations of these candidates to determine their metallicities and radial velocities, which further constrains whether the candidate stars really originated in the cluster. Combining these results with the photometric data offers a better picture of the structure of tidal streams, and allows comparison of detected stars to theoretical predictions. We present preliminary photometric and spectroscopic results. Data obtained at McDonald Observatory, Kitt Peak National Observatory, and Las Campanas Observatory. [Preview Abstract] |
Saturday, October 7, 2006 11:42AM - 11:54AM |
AP2.00007: Generation Mechanisms of S-Bursts Observed from the FAST Satellite: Data and Simulation Comparison Yi-Jiun Su, Samuel Jones, Robert Ergun, Fran Bagenal, Scott Parker Measurements of S-bursts in decametric radio emissions from the Jovian ionosphere comprise less than 10{\%} of the total observations. Electron acceleration or modulation may provide the physical mechanism that transfers energy from the Alfv\'{e}n wave to the S-burst. The modulated electron fluxes, in turn, may generate or modulate the generation of the S-burst emissions. The most successful explanation proposed for the generation radio emission from magnetized planets is the electron cyclotron maser in which radiation excited near the local electron cyclotron frequency is amplified through a gyroresonant interaction. Two types of electron cyclotron maser have been suggested: loss-cone maser due to the magnetic mirror and shell maser due to the parallel electric field in an anti-planetward current region. The first Earth-based S-burst observation was found to be associated with Alfv\'{e}n waves and electron acceleration signatures. In this presentation, we will suggest that both loss-cone and shell electron distributions can be generated in a dynamic region associated with propagating Alfv\'{e}n waves. [Preview Abstract] |
Saturday, October 7, 2006 11:54AM - 12:06PM |
AP2.00008: ABSTRACT WITHDRAWN |
Saturday, October 7, 2006 12:06PM - 12:18PM |
AP2.00009: A Physical Model And A Critical Test Melvin Cook The particle model requires the use of independent postulates to explain various phenomena. This suggests the particle model is invalid. The distribution of a system in an undulatory state is derived and an interaction of such a system that generates the complex conjugate required for a real product is identified. A successful critical test of these elements of physical reality is achieved by examination of the products of weak decays of the neutral kaons. Based on determinism and local causality for the transitions of individual systems, they generate a classical probability identical in mathematical form to the Born probability postulate, provide a local mechanism for EPR correlations, explain wave-particle duality as a transition without requiring renormalization of particle self-energy, explain the measurement process, allow direct derivations of uncertainty relationships and give rise to irreversibility on the microscopic level. [Preview Abstract] |
Saturday, October 7, 2006 12:18PM - 12:30PM |
AP2.00010: Correlation of Parsec-scale Jet Speed and Strength of Radio Nucleus in Lobe-dominated Quasars David Hough, Eric Danielson, Alexander Webb Statistical studies of samples of quasars with a wide range of jet orientations can provide valuable constraints on relativistic jet models. We are engaged in a long-term study of 25 lobe-dominated quasars from the 3CR survey. To date, VLBI observations of the parsec-scale jets in their nuclei have been used to measure (or set limits on) apparent transverse jet speeds in 14 objects. These speeds range from 0 to 8c (for Hubble constant 70 km/s/Mpc), which implies bulk Lorentz factors ranging up to 8. We find that these speeds correlate very well (99 per cent confidence level) with the fractional strength of the radio nucleus, which is defined as the ratio of nuclear to extended emission at 5 GHz emitted. There is no significant correlation with an estimated pseudoangle of each jet to our line of sight, and absolutely no correlation with projected linear size. We will discuss implications for relativistic jet models. [Preview Abstract] |
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