Bulletin of the American Physical Society
Fall 2009 Meeting of the Four Corners Section of the APS
Volume 54, Number 14
Friday–Saturday, October 23–24, 2009; Golden, Colorado
Session F5: Astronomy and Astrophysics |
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Chair: Stephan LeBohec, University of Utah Room: Green Center 265 |
Saturday, October 24, 2009 8:00AM - 8:12AM |
F5.00001: Development of a Stellar Intensity Interferometry System at StarBase Utah David Kieda, Stephan Lebohec, Paul Nunez, Benjamin Adams, Ryan Price The Intensity Interferometry technique (II) has the potential to open up high-resolution stellar imaging into frequency bands which are traditionally inaccessible to classical Michelson Interferometry (such as UBV). The II technique requires use of very large area optical dishes (3-10 meter diameter or greater), distributed over baselines of tens to hundreds of meters, in order to reconstruct high resolution images of stellar disks. Next generation ground-based gamma-ray telescope arrays (such as CTA and AGIS) involve kilometer scale telescope arrays of up to one hundred large light collectors (8-20 m diameter), allowing development of a modern implementation of the Intensity Interferometry technique pioneered by the Narrabri Stellar Intensity Interferometer nearly fifty years ago. In this talk I will describe the science capabilities of the Stellar Intensity Interferometer technique, and describe the progress achieved in developing a modern Stellar Intensity Interferometry System with a pair of new 3 m diameter optical telescopes located at StarBase Utah. [Preview Abstract] |
Saturday, October 24, 2009 8:12AM - 8:24AM |
F5.00002: Status of the Frisco Peak Observatory Paul Ricketts, Wayne Springer, Kyle Dawson, Dave Kieda, Paolo Gondolo, Adam Bolton The University of Utah has constructed an astronomical observatory located at an elevation of approximately 9600 feet of Frisco Peak west of Milford, Utah. This site was chosen after performing a survey of potential observatory sites throughout Southern Utah. At the time of writing this abstract, the dome and control buildings have been completed. Installation of a 32'' telescope manufactured by DFM Engineering is scheduled to start October 5, 2009. Commissioning of the telescope will take place this fall. A study of the photometric quality of the observatory site will be performed as well. A description of the observatory site survey and the construction and commissioning of the Frisco Peak Observatory will be presented. [Preview Abstract] |
Saturday, October 24, 2009 8:24AM - 8:36AM |
F5.00003: Global Magnetic Reversal in a Rapidly Rotating Sun Nicholas J. Nelson, Benjamin P. Brown, Juri Toomre Global MHD simulations of the solar convection zone and a tachocline of shear at its base have demonstrated that strong bands of toroidal magnetic field can be built in the tachocline through stretching and organizing of small-scale fields pumped downward from the convection zone. Recent 3D simulations of more rapidly rotating suns have revealed that global-scale wreathes of toroidal magnetic field can be achieved in the bulk of the convection zone itself, remarkably even without a tachocline present. Continuing this work, we have carried out new simulations at higher turbulence levels in a sun-like star rotating at three times the solar rate. We obtain toroidal magnetic wreathes which have large temporal variations in field strength as they interact with turbulent convection and global differential rotation, yet they continuously rebuild themselves, persisting in the bulk of the convection zone for thousands of days. These magnetic structures can even undergo a reversal of global magnetic polarity. We describe here the properties of these structures and the nature of such a reversal. [Preview Abstract] |
Saturday, October 24, 2009 8:36AM - 8:48AM |
F5.00004: New Astrophysics Research Opportunities at BYU Victor Migenes MASER emission with astrophysical origin was proposed in the early 1960s. Since the discovery, a few years later, maser physics and high- spatial resolution research have become a major tool for studying the kinematical and dynamical conditions in a number of important astrophysical settings, like: star formation, late-type stars, supernovae remnants and other galaxies. Improvements in technology and interferometric techniques in radio astronomy have allowed the most detailed study of maser sources so far. MASER emission properties like high specific intensity, compact size, polarization and variability, among others, have been invaluable in helping us understand the conditions and physical processes in these regions. We discuss the status of present research and the new research opportunities at BYU. [Preview Abstract] |
Saturday, October 24, 2009 8:48AM - 9:00AM |
F5.00005: OH Megamasers in Galactic Merging Regions Kirstin Cooprider, Victor Migenes OH Megamasers (OHM) very often appear in highly luminous infrared emission regions. One of these regions that are of great scientific significance is galactic mergers. OH masers are normally characterized by their presence in dusty star formation regions. However OH megamasers may not necessarily be represented only by their association with star formation, because of the possibility of a compact AGN. AGNs can also provide the driving mechanism for the masing process. Previously classified Starburst galaxies where OH masers are normally found, are now optically observed as AGN. OHMs may also be a reasonable judge as to the evolutionary stage of the merger. This project focuses on the radio observations that are part of a multi-frequency analysis of the merging regions surrounding the known OHMs. HI observations show where the gas is and help to determine the column density of the gas in the OHM regions. H$\alpha$ maps the excited gas. Radio data will give position information of OHMS. Just as the environment provides a basis for the properties of the maser components, so do the maser components determine the properties of the environment. [Preview Abstract] |
Saturday, October 24, 2009 9:00AM - 9:12AM |
F5.00006: Rare Detections of OH MASERS in Star Forming Regions Derek Felli, Victor Migenes MASERs (Microwave Amplification by Stimulated Emission of Radiation) appear from a variety of molecules and they originate from dense clumps of molecular gas. MASERs are some of strongest radio wave emitters in the observable universe. Due to their compact nature interferometry techniques is the best method to study the emission. The VLBA-NRAO instrument was used to study MASERs to further understand how stars form. Radio observations are used because at the early stages of star formation dust prevents optical studies. OH MASER emission has 4 strong transitions at 1.612, 1.665, 1.667 and 1.720 GHz. In star forming regions it is common to detect MASERs at 1.665 and 1.667 GHz. Detections at 1.612 and 1.720 GHz are rare in star forming regions but have been detected in Orion-KL, W3 and W75N which are high mass star forming regions. Detections of the 1.612 and 1.720 GHz transitions in this study may give further evidence that only high mass star forming regions produce these transitions though we don't understand why, yet. Because these transitions haven't been exhibited in low star mass forming regions, it may be the link to classify several unknown star forming regions as low mass or high mass star formation. We present and discuss some of our preliminary results. [Preview Abstract] |
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