Bulletin of the American Physical Society
Annual Meeting of the Four Corners Section of the APS
Volume 57, Number 11
Friday–Saturday, October 26–27, 2012; Socorro, New Mexico
Session H2: Radio Interferometry/Other |
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Chair: Crystal Anderson, New Mexico Institute of Mining and Technology Room: Macey Center Auditorium |
Saturday, October 27, 2012 10:12AM - 10:36AM |
H2.00001: The Expanded Very Large Array Project Invited Speaker: Rick Perley The Expanded Very Large Array Project, begun in 2001, is now completed -- on time, on budget, and ``on spec.'' The major goal of the project was to multiply the key observational capabilities of the Very Large Array -- the world's most powerful, versatile, and productive radio telescope -- by a factor of at least an order of magnitude by implementation of modern technologies. The result of the project is an operationally new telescope -- renamed the Jansky Very Large Array -- which is capable of new science unimagined in 1980, when the original VLA was completed. In this talk, I will review the goals of the project, and describe the new capabilities of the Jansky Very Large Array. Already, the array is providing fabulous new insights into the physics of the universe,and I will spend the majority of the time describing examples of new results. [Preview Abstract] |
Saturday, October 27, 2012 10:36AM - 10:48AM |
H2.00002: JVLA Observations of Massive Protostars Viviana Rosero, Peter Hofner Massive stars play a key role in the structure and evolution of galaxies since they dominate the nature of the interstellar medium. However, the mechanism of formation for massive stars is not well known to date due to their location in complicated cluster environments, large distances and high obscuration. One of the key questions of modern astronomy is if there is any link between low mass and high-mass star formation. We want to investigate the type of emission of these objects and the ejection and the accretion phenomena. We are working on a JVLA high resolution and high sensitivity survey of $\sim$60 cold molecular cores and hot molecular cores which are the earliest stage of massive star formation. In this work, I will present preliminary results from the survey and some detail examples. [Preview Abstract] |
Saturday, October 27, 2012 10:48AM - 11:00AM |
H2.00003: The first station of the Long Wavelength Array (LWA1) Frank Schinzel Construction of the first station of the Long Wavelength Array (LWA1) was completed 1.5 years ago. The LWA1 has since been undergoing commissioning and its first science observations from two calls for proposals. The LWA1 is co-located with the Very Large Array and consists of 258 dual-polarization dipoles, the signals of which are digitized and combined into beams. Four independently-steerable dual-polarization beams are available, each with two tunings of 16 MHz bandwidth that can be independently tuned to any frequency between 10 and 88 MHz. On behalf of the LWA1 collaboration, I am going to present a brief overview of the station architecture and early science results demonstrating the versatile capabilities of this new instrument. [Preview Abstract] |
Saturday, October 27, 2012 11:00AM - 11:12AM |
H2.00004: An ALMA and ATCA Molecular Line Survey toward Centaurus A Juergen Ott, David Meier, Mark McCoy, Sebastien Muller, Alison Peck, Violette Impellizzeri, Fabian Walter, Susanne Aalto, Christian Henkel, Sergio Martin, Paul van der Werf, Ilana Feain, Crystal Anderson We present Atacama Large Millimeter/submillimeter Array and Australia Telescope Compact Array data of molecular absorption lines toward the bright central core of Centaurus A. The line of sight crosses the prominent dust lane and continues through the disk and eventually through gas that may be very close to the central supermassive black hole. The goal of our the survey is to determine the physical conditions of the gas via analyses of molecular line tracers including molecular abundances and excitation conditions that are sensitive to changes in temperature, density, ionization, and shocks. This study allows us to derive the physical conditions of each absorption line complex and allows us to define the main process shaping its environment. We present a first analysis of our data in the 13, 7, 3, and 1mm wavebands. [Preview Abstract] |
Saturday, October 27, 2012 11:12AM - 11:24AM |
H2.00005: Differential Proper-Motion Measurements of The Cygnus Egg Nebula; The Presence of Fast Equatorial Outflows Rachael Tomasino, Toshiya Ueta, Brian Ferguson We present the results of differential proper-motion analyses of the dust shell structure in the Egg Nebula (RAFGL 2688, V1610 Cyg), based on the archived two-epoch imaging-polarimetric data in the optical taken with the Hubble Space Telescope. We measured the amount of motion of local structures and the signature concentric arcs in the nebula by determining their relative shifts over an interval of 7.25 yr. We discovered that the optical polarization characteristics of the Egg Nebula was influenced by the marginal optical thickness of the circumstellar shell and the illumination of the nebula was done in two-step mechanism - most of the nebula is illuminated by the secondary/dust-scattered starlight emanating from the bipolar lobes themselves due to the central concentration of dust grains of more than 10$^3$ AU diameter that regulates the seepage of the starlight from the central region. Nevertheless, based on two types of differential proper-motion analyses we revealed interesting dynamics of the lobes and concentric arcs, which should provide solid constraints on the subsequent theoretical/numerical investigations. [Preview Abstract] |
Saturday, October 27, 2012 11:24AM - 11:36AM |
H2.00006: Disks of Fire and Water: On the Coexistance of Hydroxyl and Water Megamasers Brandon Wiggins, Victor Migenes Hydroxyl and water megamasers are employed in the study of the internal kinematics of distant galaxies. OH masers are radiatively pumped through FIR photons, while water masers have been found to be pumped collisionally at higher densities and temperatures. The pumping mechanisms appear to be mutually exclusive which is supported observationally by the fact that specimens exhibiting masing in both varieties are nearly non-existent. In this presentation, we report the results of a study of NGC 3079, an object which exhibits masing activity from both water and OH maser species and seek to shed additional light on the possibily unique physical processes taking place within this object. Interferometric data from the European Very Long Baseline Interferometry Network (EVN) were reduced using the AIPS software suite. We detect the molecular disk in NGC 3079 and superimpose the OH maser reported in Baan et al. (1995). Archival data of radio continuum emission on the kiloparsec scale suggests an outflow with a position angle differing significantly from the outflows on subparsec scales, perhaps indicating the presence of a precessing jet to power outflows. A warped/precessing disk model is proposed to explain the wide angle outflow and chaotic structure of the molecule disk. Brief discussion is provided on the OH maser discussed in Baan et al. (1995). [Preview Abstract] |
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