Bulletin of the American Physical Society
2007 APS April Meeting
Volume 52, Number 3
Saturday–Tuesday, April 14–17, 2007; Jacksonville, Florida
Session T11: Gravitational Wave Astronomy |
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Sponsoring Units: DAP GGR Chair: Isabel Leonor, University of Oregon Room: Hyatt Regency Jacksonville Riverfront City Terrace 7 |
Monday, April 16, 2007 1:30PM - 1:42PM |
T11.00001: Rates and characteristics of intermediate-mass-ratio inspirals detectable by Advanced LIGO Ilya Mandel, Duncan Brown, Jonathan Gair, M. Coleman Miller We discuss the event rates and characteristics of intermediate-mass-ratio inspirals (IMRIs) of compact objects into intermediate-mass black holes (IMBHs) in globular clusters that may be in the detection range of Advanced LIGO. We comment on the astrophysical background of these events, suggest estimates of rates per globular cluster, discuss the distance sensitivity of LIGO and show that Advanced LIGO may see up to tens of IMRIs per year, though one per year may be a more plausible value. We analyze several possible capture mechanisms, and conclude that most IMRIs will have circularized by the time they are in the Advanced LIGO band. [Preview Abstract] |
Monday, April 16, 2007 1:42PM - 1:54PM |
T11.00002: Beating the Crab pulsar spin-down and other upper limits: new results from the LIGO S5 known pulsar search Matthew Pitkin Using more than a year's worth of data from the fifth science run of the LIGO gravitational wave observatories we have set upper limits on the strength of gravitational wave emission from a selection of millisecond and young pulsars. The selected pulsars include many within binary systems and globular clusters, and also include the two pulsars with the highest known spin-down rates: the Crab pulsar and PSRJ0537-6910. For all these selected pulsars we provide either completely new upper limits or improvements on previously measured values. For the first time we are able to constrain the gravitational wave emission from the Crab pulsar to a value that is significantly lower than that based on simple energy conservation and spin-down arguments. We discuss how this important null result allows us to constrain the energetics of the Crab pulsar more tightly and make meaningful deductions about its equation of state. [Preview Abstract] |
Monday, April 16, 2007 1:54PM - 2:06PM |
T11.00003: Broadband Search for Continuous-Wave Gravitation Radiation with LIGO Vladimir Dergachev Isolated rotating neutron stars are expected to emit gravitational radiation of nearly constant frequency and amplitude. Searches for such radiation with the LIGO interferometers are underway, using data taken from LIGO's first several data runs. Because the gravitational wave signal amplitudes are thought to be extremely weak, long time integrations must be carried out to detect a signal. Unfortunately, motion of the Earth (daily rotation and orbital motion) induces substantial modulations of detected frequency and amplitude that are highly dependent on source location. We present an algorithm called PowerFlux, used to account for these modulations, when summing power spectral density estimates incoherently over long time intervals. Current approaches to reconstruction of source parameters (necessary for coincidence analysis) will also be discussed. We will describe the application of PowerFlux to a broadband search in data from the 30-day fourth LIGO Science Run (S4) and to the initial data of the ongoing S5 run. [Preview Abstract] |
Monday, April 16, 2007 2:06PM - 2:18PM |
T11.00004: Search for gravitational waves from compact binary systems in the third and fourth LIGO science runs. Thomas Cokelaer We report on a search for gravitational waves from compact binary systems during the third and fourth LIGO science runs. In our analysis, we considered compact binary systems made of two primordial black holes, or two neutron stars, or two binary black holes, with a total mass between 0.6 and 40.0 solar mass. We analysed more than 1300 hours of coincident data between at least two of the LIGO interferometers. We describe the different aspects of the search for gravitational waves which emcompass software injections, background estimate, and the challenge of detecting the presence of binary signal in the LIGO data. We present here the preliminary results which arise from this search for each of the binary system considered. [Preview Abstract] |
Monday, April 16, 2007 2:18PM - 2:30PM |
T11.00005: Parameterized equations of state for neutron stars Jocelyn Read Substantial uncertainty remains in the equation of state of matter above nuclear density. A range of plausible equations of state have been proposed with varying assumptions about underlying physics. Progress is reported on using piecewise polytropes to create a generalized analytic equation of state with a small number of parameters that is sufficient to capture the features of a wide range of candidate equations of state. Astrophysical observations can then be used to systematically constrain the parameter space instead of ruling out individual equations of state. In particular, we consider potential constraints set by observation of gravitational waves from binary neutron star inspiral using Advanced LIGO with narrow banding. [Preview Abstract] |
Monday, April 16, 2007 2:30PM - 2:42PM |
T11.00006: All-sky LIGO Search for Periodic Gravitational Waves in the S4 Data Keith Riles We report on an all-sky search with the LIGO detectors for periodic gravitational waves in the frequency range 50-1000 Hz and having a negative frequency time derivative with magnitude between zero and 10$^{-8}$ Hz/s. Data from the fourth LIGO science run (S4) have been used in this search. Three different semi-coherent methods of summing strain powers have been used; their respective advantages and disadvantages will be discussed. Observing no evidence of periodic gravitational radiation, we report upper limits on strain amplitude and interpret these limits to constrain radiation from rotating neutron stars. [Preview Abstract] |
Monday, April 16, 2007 2:42PM - 2:54PM |
T11.00007: Search for Gravitational Wave Radiation Associated with the Pulsating Tail of the SGR 1806-20 Hyperflare Luca Matone We present the sensitivity for Gravitational Waves (GWs) associated with the X-ray pulsating tail of the SGR 1806-20 hyperflare of December 27, 2004 using the LIGO Hanford (WA) 4km detector. The search targeted potential quasi-monochromatic GWs lasting for tens of seconds and emitted at the observed Quasi-Periodic Oscillation (QPO) frequencies and their second harmonics. Using a simple source model, we illustrate the astrophysical significance of this result by comparing the corresponding characteristic energy allowed in GWs to the total energy estimated to have been emitted in the observable electromagnetic spectrum. This analysis provides a means to probe the energy reservoir of the source at realistic levels and represents the first broadband asteroseismology measurement using a GW detector. [Preview Abstract] |
Monday, April 16, 2007 2:54PM - 3:06PM |
T11.00008: UFLIS: The University of Florida LISA Interferometry Simulator Yinan Yu, Sridhar Reddy Guntaka, Rachel J. Cruz, James I. Thorpe, Shawn Mytrik, D.B. Tanner, Guido Mueller The Laser Interferometer Space Antenna (LISA) is a joint NASA/ESA observatory aimed to detect gravitational waves from astrophysical sources such as like mergers between super-massive black holes and galactic binary systems. LISA will measure changes in the separation between free falling proof masses separated by 5~Gm with pm accuracy (See http://lisa.nasa.gov for more information on LISA.) LISA's interferometry measurement system combines several technologies to reduce and suppress the otherwise overwhelming laser frequency noise. Over the last several years our group has been setting up UFLIS, the University of Florida LISA Interferometry Simulator. UFLIS includes LISA-like laser frequency stabilization and data acquisition systems such as LISA-like phase meter and as well as electronic phase delay units which allow us to emulate the 16~s light travel times between spacecraft. We will present the latest results and the current status of the simulator as well as discuss future plans. This work is supported by NASA/OSS grant BEFS04-0019-0019. [Preview Abstract] |
Monday, April 16, 2007 3:06PM - 3:18PM |
T11.00009: Coincidence-based Gravitational Wave Burst Searches in LIGO and Astrophysical Interpretation Keith Thorne We present the status of searches for gravitational-wave bursts (GWBs) in LIGO's current science run from coincidences between candidates based on each interferometer's data stream using single-instrument analysis methods. One such method uses Bayesian time-domain analysis (BlockNormal) to identify candidate bursts in each instrument, followed by multiple-instrument coincidence and waveform coherence tests. We show that this method is robust against single-instrument large- amplitude transients. We detail how one could extract astrophysical limits on galactic source populations of GW bursts (such as supernova core collapses) using a coincidence-based search. [Preview Abstract] |
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