Bulletin of the American Physical Society
2009 APS April Meeting
Volume 54, Number 4
Saturday–Tuesday, May 2–5, 2009; Denver, Colorado
Session C8: Instrumentation for Astrophysics |
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Sponsoring Units: DAP Chair: David Kieda, University of Utah Room: Governor's Square 17 |
Saturday, May 2, 2009 1:30PM - 1:42PM |
C8.00001: The on-orbit calibration of the Fermi Large Area Telescope Eduardo do Couto e Silva We will describe the calibrations of the Large Area Telescope (LAT) aboard the Fermi Gamma ray Space Telescope. The LAT began its on-orbit operations on June 23, 2008 using pre-launch calibration values as reference. Here we will describe on-orbit calibration results obtained using known astronomical sources, galactic cosmic rays, and charge injected onto the front--end electronics. Calibrations, defined in a generic sense, correspond to alignment in time of trigger signals, determination of detector thresholds and response, evaluation of the perimeter of the South Atlantic Anomaly (SAA), measurements of live time, of absolute time, and spatial alignment. We discuss the stability of calibration values and describe minor changes observed since the satellite launch. These calibration results are incorporated in the LAT datasets to be publicly released in Sep 2009. Work at the SLAC National Accelerator Laboratory is supported by Department of Energy contract DE--AC03--76SF00515. [Preview Abstract] |
Saturday, May 2, 2009 1:42PM - 1:54PM |
C8.00002: The Cosmic Origins Spectrograph: Design, Preflight Performance and Science Goals Steven Osterman, James Green, Cynthia Froning, Steven Penton, Stephene Beland, Michael Shull, Alessandra Aloisi, Charles Keyes, David Sahnow, Jason McPhate The Cosmic Origins Spectrograph (COS) is a new ultraviolet spectrograph which will be installed into the Hubble Space Telescope (HST) as part of the upcoming Servicing Mission 4. COS will be the most sensitive ultraviolet spectrograph ever flown aboard HST, and is optimized for observing faint, point source targets at low and moderate spectral resolutions (R$\sim $ 1500-3500 and 16,000-20,000) at wavelengths ranging from 115 nm to 320 nm. The principal scientific objectives of the mission include the study of the origins of large-scale structures in the universe, the formation and evolution of galaxies, the origin of stellar and planetary systems and the cold interstellar medium. We will present the instrument design, preflight performance, projected on-orbit capabilities, and the key scientific objectives of the mission. [Preview Abstract] |
Saturday, May 2, 2009 1:54PM - 2:06PM |
C8.00003: Advanced Characterization and Simulation of SONNE - a Fast Neutron Spectrometer for the Solar Probe Plus Mission Richard Woolf, James Ryan, Peter Bloser, Ulisse Bravar, Erwin Flueckiger, Procheta Mallik, Mark McConnell, Alexander MacKinnon, Benoit Pirard An important goal in solar physics is the measurement of neutrons in the 1-20 MeV range -- the surest indication of low energy ion acceleration in the low corona. Detection of these particles is key for understanding particle acceleration as a whole. Solar neutron measurements in this range could also have the great discovery potential of the postulated nanoflares -- possibly a significant agent for heating the solar corona. Neutrons in this energy range suffer from decay and range out prior to 1AU, measurements abroad the Solar Probe Plus mission to the inner heliosphere are needed. We report on the technical status of the ongoing characterization and simulation efforts of the SOlar NeutroN Experiment (SONNE) - a fast neutron imaging spectrometer with sensitivity to neutrons in the 1-20 MeV range. Results from a limited laboratory prototype and GEANT4 simulations will be presented. [Preview Abstract] |
Saturday, May 2, 2009 2:06PM - 2:18PM |
C8.00004: The HAWC Observatory Andrew Smith The High Altitude Water Cherenkov (HAWC) observatory is a proposed, large field of view ($\sim$2 sr), high duty cycle ($>$95\%) TeV gamma-ray detector to be constructed using a dense array of water tanks covering an area greater than 25,000$m^2$. HAWC will be located at an elevation of 4100m near the Sierra Negra mountain in Mexico. The instrument will use 900 photomultiplier tubes to observe the relativistic particles and secondary gamma rays in extensive air showers. This technique has been used successfully by the Milagro observatory to detect known, as well as new, TeV sources. The PMTs and much of the data acquisition system of Milagro will be reused for HAWC, resulting in a cost effective detector that can be built quickly (2-3 years). The improvements of HAWC will give 15 times the sensitivity of Milagro. I will present the results of recent detector optimization and engineering studies for HAWC as well as present a detailed analysis of the flux and energy sensitivity of the proposed instrument. [Preview Abstract] |
Saturday, May 2, 2009 2:18PM - 2:30PM |
C8.00005: The Nano-HAWC Engineering Array John Pretz The High Altitude Water Cherenkov (HAWC) experiment is the proposed second-generation of the Milagro experiment and will utilize 900 Photo-multiplier Tubes deployed in tanks of water a high altitude. The experiment will be sensitive to TeV extensive air showers induced by high-energy particle interactions in the atmosphere. As a first step in the development of the HAWC array, a small engineering array named nano-HAWC, is being deployed at the HAWC site at the Sierra Negra mountain in Mexico. This modest array will consist of a few tanks and a simple data-acquisiton system, demonstrating the viability of the HAWC site and providing a vechicle to test technologies for HAWC. I will describe the development of the HAWC site and the report on the status of the construction of the nano-HAWC array. [Preview Abstract] |
Saturday, May 2, 2009 2:30PM - 2:42PM |
C8.00006: Surveying the TeV Sky with the High Altitude Water Cherenkov (HAWC) Observatory Brenda Dingus The highest energy gamma rays probe Nature's particle accelerators and the physical mechanisms operating in these extreme sources. The flux from these TeV accelerators decreases with gamma ray energy and in many cases is rapidly and unpredictably variable. A detector, such as the HAWC observatory with its wide field of view of $\sim $ 2 steradians and nearly 100{\%} duty factor, will enable new observations of the TeV sky. The large area and good background rejection will allow spectral measurements to $>$100 TeV which are key to determining the sources of Galactic cosmic rays. And the HAWC sensitivity at $<$1 TeV is sufficient to detect flaring active galactic nuclei and search for the predicted prompt emission from gamma-ray bursts. However, the most exciting results will likely come from the unpredicted observations enabled by HAWC's unbiased survey of the entire Northern Hemisphere sky. [Preview Abstract] |
Saturday, May 2, 2009 2:42PM - 2:54PM |
C8.00007: Introduction of new radio array in collaboration with Tunka-133 effort Mark Stockham An overview of the hardware involved in the radio antenna effort as part of the Tunka-133 EAS Cherenkov Array will be given. There are currently two radio antennas sensitive to frequencies of 40-200 MHz, with planned expansion to six total antennas in July 2009. The DAQ and integration with the Tunka-133 Array will be summarized. Preliminary results will be shown. [Preview Abstract] |
Saturday, May 2, 2009 2:54PM - 3:06PM |
C8.00008: Results of the radio-detection experiment HASRA (Hawaii Askaryan in Salt Radio Array) Radovan Milincic Measurements of the radio emission associated to Ultra High Energy Cosmic Ray particles interaction with dense dielectric material provide an effective method for their detection and exploration. The Hawaii Askaryan in Salt Radio Array (HASRA) was built to explore possibility of detection of coherent radio Cherenkov emission in rock salt from interaction of cosmic ray protons and Air Shower particles. Performance of the detector, the implemented detection techniques, and results of 1 year long measurement of Askaryan effect from CR particles with energy above 100 GeV will be reported. Also potential of future detectors utilizing radio techniques in rock salt will be discussed. [Preview Abstract] |
Saturday, May 2, 2009 3:06PM - 3:18PM |
C8.00009: A new look on Intensity Interferometry Paul Nunez, Stephan Le Bohec, David Kieda, Richard Holmes Intensity interferometry was introduced in the 1950's and implemented in the late 1960's with the Narrabri Interferometer. Very high angular resolution at visible wavelengths made it possible to measure stellar diameters of a few milli-arc-seconds. Air Cherenkov telescope arrays used for high energy gammaray astronomy can provide perfect sites for a revival of Intensity Interferometry in the optical region. Also, improvements in technology make the implementation of Intensity Interferometry easier and can improve sensitivity. Novel ideas on phase recovery also make it possible to reconstruct high resolution optical images of astrophysical objects in a model independent way. The capabilities and limitations of modern intensity interferometry are discussed. [Preview Abstract] |
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