Bulletin of the American Physical Society
2012 Annual Fall Meeting of the APS Prairie Section
Volume 57, Number 14
Thursday–Saturday, November 8–10, 2012; Lawrence, Kansas
Session A1: Astrophysics, Cosmology and Space Science I |
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Chair: Gregory Rudnick, University of Kansas Room: Oread Hotel Hancock Room |
Friday, November 9, 2012 8:30AM - 9:05AM |
A1.00001: The Future of Supernova Cosmology Invited Speaker: Nicholas Suntzeff It has been 12 years since the discovery of the acceleration of the expansion of the Universe by the Supernova Cosmology Project and the High-Z Supernova Search Team. The initial discovery was based on luminosity distances to Type Ia (thermonuclear) supernovae, out to redshifts of z$=$0.8. A simple description of the discovery is that Type Ia supernovae at redshifts of z$=$0.6 are too faint by 0.25 magnitudes with respect to an empty universe. The nearby supernovae used in these projects, which came primarily from the Cal\'{a}n/Tololo Supernova Survey, also were the key objects that defined the near field Hubble flow, leading to the most precise measurements of the Hubble constant \textit{H0} when combined with physical distances to a small number of galaxies hosting Type Ia supernovae. Another key observation, made by the Higher-Z Supernova Team, was the Type Ia supernovae at redshifts greater than z$=$1 show clear evidence of deceleration, as expected from a simple cosmology with \textit{Omega\textunderscore matter}$=$0.23 and \textit{Omega\textunderscore Lambda}$=$0.74. With the addition of measurements of the Baryon Acoustic Oscillations in the local volume, weak lensing of distant galaxies, the formation of large scale structure, and the CMB temperature fluctuations, we have now arrived at a (optimistically named) concordance cosmology which so far has the curvature \textit{Omega\textunderscore k}$=$1 and Lemaitre's \textit{equation of state parameter w}$=$-1.0 to 10{\%} or so, with no meaningful measurement of any time rate of change of ``dark energy.'' A number of major surveys (SNLS, ESSENCE, SDSSIII) have finished, and larger surveys have been started (DES). Even larger surveys are being planned and built (LSST, Pan-STARRS). I will discuss the present status of cosmology and the supernova data for these projects, and give a glimpse of what is ahead. [Preview Abstract] |
Friday, November 9, 2012 9:05AM - 9:17AM |
A1.00002: The Peculiar Emission-line Object Tololo 26 Steven Hawley, Howard Bond, Reginald Dufour Tololo 26 was identified in 1976 as a planetary nebula (PN) with peculiar line ratios, in particular [O III] $\lambda $4363/H$\gamma $ estimated \textgreater 1. Hawley (1981) obtained a detailed spectrum, which showed no [O II] or [N II] and a $\lambda $4363/H$\gamma $ ratio of \textgreater 2.0, all unusual for PN and indicative of high electron density. Hawley suggested that Tol 26 could show spectral changes over time. In 2011 spectra were obtained confirming a change in [O III]/H$\beta $. Analysis of the original spectrum implied a small amount of high-density ionized gas, occupying a region smaller than the solar system. Estimates from the 2011 spectrum are consistent with a decrease in density and temperature. BVRI colors obtained in 2012, combined with GALEX and 2MASS observations, describe an SED that can be fitted with contributions from a 100,000K WD, a G2 V companion and dust components at 1350K and 200K. This makes Tol 26 the second object, along with EGB 6, proposed to be a PN with emission lines coming from a small amount of ionized gas associated with a cool companion to the white dwarf. We propose that an accretion disk is formed around the companion during the PN formation phase. Tol 26 and EGB 6 could be precursors to barium stars and certain PN central stars with rapidly rotating companions. [Preview Abstract] |
Friday, November 9, 2012 9:17AM - 9:29AM |
A1.00003: The Pierre Auger Research and Development Array -- Goals and Status Holger Meyer The Pierre Auger Collaboration operates a detector for ultra-high-energy cosmic rays near Malarg\"ue, Argentina. It consists of a surface detector array of more than 1600 surface detectors covering an area of roughly 3000 km$^2$ and a fluorescence detector consisting of 24 telescopes in four buildings. The Research and Development Array (RDA) is currently being set up south of Lamar, CO to test possible upgrades to the Southern site, to evaluate the performance of the surface detectors in the environment of Eastern Colorado, and to provide a test bed for other related detector development. We present an overview of these goals and describe the current status of the RDA. [Preview Abstract] |
Friday, November 9, 2012 9:29AM - 10:04AM |
A1.00004: IceCube - Performance and first results Invited Speaker: Albrecht Karle The IceCube detector, which completed construction in December 2010, is the first km$^3$ scale instrument to become operational with the primary mission of observing high energy neutrinos from astrophysical sources. All three flavors of neutrinos are detectable with IceCube over a wide energy range. The detector is also being used for studying atmospheric neutrinos, cosmic rays and other physics. I will discuss some performance characteristics of the completed detector and report on results from the partially completed detector on searches for diffuse astrophysical neutrinos, astrophysical point sources of neutrinos and neutrino emission coincident with gamma ray bursts. I will also present results on the observation of neutrino oscillations and discuss the potential program for neutrino oscillation studies. [Preview Abstract] |
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