Bulletin of the American Physical Society
2009 APS April Meeting
Volume 54, Number 4
Saturday–Tuesday, May 2–5, 2009; Denver, Colorado
Session R11: Gravitational Wave Astrophysics |
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Sponsoring Units: GGR DAP Chair: Stan Whitcomb, LIGO Lab/Caltech Room: Plaza Court 1 |
Monday, May 4, 2009 1:30PM - 1:42PM |
R11.00001: Gravitational Waves from Convection, the Standing-Accretion-Shock Instability and the Onset of Explosion in Core-Collapse Supernovae Christian D. Ott, Jeremiah W. Murphy, Adam Burrows We present new results on the gravitational wave (GW) emission in the postbounce phase of nonrotating or slowly rotating core-collapse supernovae obtained from an extensive set of simulations with the 2D code BETHE/Hydro. Our calculations include the most recent presupernova stellar models, a finite-temperature nuclear equation of state and a prescription for neutrino cooling and heating. Investigating the postbounce evolution of progenitors of 12, 15, 20, and 40 solar masses with multiple parametrized neutrino luminosities, we for the first time establish the systematics with progenitor star mass and neutrino luminosity of the GW signal emitted by neutrino-driven convection and the standing-accretion-shock instability. In addition, we identify the GW signal associated with the onset of a neutrino-driven core-collapse supernova explosion. [Preview Abstract] |
Monday, May 4, 2009 1:42PM - 1:54PM |
R11.00002: Gravitational Waves from Core Collapse Supernova: Simulations with CHIMERA Konstatin Yakunin, Stephen Bruenn, Pedro Marronetti We perform numerical simulations of Core Collapse Supernova using the multi-dimensional hydrodynamics code CHIMERA that includes a realistic nuclear networks, spectral neutrino transport, approximate GR, and a realistic EOS. Gravitational wave signals from different progenitor stars (12, 15, 20 and 25 solar masses) generated by both matter and neutrinos will be presented. We compare our results with other groups and analyze some features of the core-collapse supernova mechanism. These GW templates can be used to enhance the search for supernovae signals in current and future laser-interferometric gravitational wave detectors. [Preview Abstract] |
Monday, May 4, 2009 1:54PM - 2:06PM |
R11.00003: Extracting equaation of state parameters from inspiral waveforms John L. Friedman, Jocelyn Read, Harris Markakis, Masaru Shibata, Koji Uryu, Jolien Creighton, Keisuke Taniguchi In this and a companion talk by Markakis, we report the results of first studies that that use numerical simulations of binary inspiral to estimate the accuracy with which gravitational wave observations of binary inspiral can determine parameters of the neutron-star equation of state. We use a parameterized equation of state (previously obtained in work with B.D. Lackey and B.J. Owen) based on piecewise polytropes. The EOS is chosen to make the number of parameters smaller than the number of neutron-star properties that have been measured or will have been measured in the next several years and large enough to accurately approximate the large set of candidate EOSs. Knowing the mass of the neutron star(s) in a neutron-star-neutron-star or neutron-star-black-hole binary allows one to use the inspiral waveform to reduce the equation-of-state parameter space by one dimension; the EOS is restricted to a surface associated with the measured departure from point-particle waveform. We estimate the accuracy with which one can extract a parameter transverse to that surface and the accuracy with which one can estimate neutron star radius. [Preview Abstract] |
Monday, May 4, 2009 2:06PM - 2:18PM |
R11.00004: The Neutron Star Equation of State and Gravitational Wave Observations Charalampos Markakis, Jocelyn S. Read, Masaru Shibata, Koji Uryu, Jolien D. E. Creighton, John L. Friedman Properties of the neutron star equation of state can potentially be measured via gravitational wave observations, by measuring departures from the point-particle limit of the waveform produced in the late inspiral of a neutron star binary. Numerical waveforms from simulations of inspiraling neutron star binaries, computed for equations of state with varying stiffness, are compared. As the stars approach their final plunge and merger, the gravitational wave phase accumulates more rapidly for smaller values of the neutron star compactness. This suggests that gravitational wave observations at frequencies around $\sim $1 kHz will be able to measure a compactness parameter and constrain the possible neutron star equations of state. [Preview Abstract] |
Monday, May 4, 2009 2:18PM - 2:30PM |
R11.00005: The Breakin Strain of Neutron Star Crust and Continuous Gravitational Wave Radiation C.J. Horowitz, K. Kadau, J. Hughto, D.K. Berry Mountains on rapidly rotating neutron stars efficiently radiate gravitational waves. The maximum possible size of these mountains depends on the breaking strain of neutron star crust. We use large scale molecular dynamics simulations of Coulomb solids to determine the breaking strain. We find that the breaking strain of small single crystals is very large and that this strength is only modestly reduced by impurities, defects, and grain boundaries. Therefore, neutron star crust is likely very strong and can support mountains large enough so that their gravitational wave radiation could limit the spin periods of some stars and might be detectable in large scale interferometers. [Preview Abstract] |
Monday, May 4, 2009 2:30PM - 2:42PM |
R11.00006: Astrophysics with gravitational-wave measurements of binary compact object mass distributions Richard O'Shaughnessy, Chris van Den Broeck, Chris Belczynski Future gravitational wave detectors (advanced LIGO; Virgo) will detect tens to hundreds of few-stellar-mass binary compact object coalescences (CBCs) in the local universe, providing a detection-weighted sample of their mass distribution. We describe how efficiently the observed number and mass distribution can discriminate between different CBC source population models, both abstractly and by explicit comparisons to an archive of binary population synthesis simulations. Finally, proposed future instruments like the Einsten Telescope and other third-generation interferometers, with only a moderate (x10) increase in range range, could detect tens to hundreds of thousands of sources well into the epoch of peak star formation (z$\sim$4). ``Gravitational-wave tomography'' will be possible, providing data products including a map of the low-redshift universe as seen in binaries and a redshift-dependent mass distribution. We describe how future detectors could use this information to provide exquisitely precise constraints on our understanding of CBC formation. [Preview Abstract] |
Monday, May 4, 2009 2:42PM - 2:54PM |
R11.00007: Estimating the parameters of non-spinning binary black holes using ground-based gravitational-wave (GW) detectors: Statistical errors Sukanta Bose, P. Ajith We assess the statistical errors in estimating the parameters of non-spinning black-hole binaries using ground-based GW detectors and discuss their cosmological implications. While past assessments were based on partial information provided by only the inspiral and / or ring-down pieces of the coalescence signal, our projections use ``complete'' inspiral-merger-ringdown waveforms, and employ the Fisher-matrix formalism, vetted by Monte-Carlo simulations. Parameter accuracies of the complete waveform are found to be significantly better than those of just the inspiral waveform. In the Advanced LIGO detector, parameter estimation is the most accurate in the total-mass range $M \approx 100-200 M_\odot$. For $M \approx 100 M_\odot$ systems, the errors in measuring $M$ and the mass-ratio are reduced by an order of magnitude or more compared to waveforms of the inspiral phase alone. Moreover, for $M \approx 100 M_\odot$ systems at distances of 1 Gpc, we estimate that an Advanced LIGO-Virgo type network is capable of determining the sky-position with an accuracy of from about 0.01 square-degree to a square-degree, with a mean of nearly 0.1 square-degree. The sky-averaged fractional error in its distance is about 20\%. [Preview Abstract] |
Monday, May 4, 2009 2:54PM - 3:06PM |
R11.00008: Distinguishing GRB progenitors: An application of Maximum Entropy Gravitational-wave Data Analysis Ruxandra Bondarescu, Ravi Kumar Kopparapu, Lee Samuel Finn, Tiffany Summerscales What are the progenitors of short duration Gamma Ray Bursts (GRBs)? Theory predicts a variety of short GRB models with Neutron Star - Neutron Star binary mergers and the tidal disruption of a neutron star by a black hole being the most favored scenarios. Will the emitted gravitational radiation help in distinguishing between different types of progenitors? Can the gravitational radiation emitted by a long duration GRB source be confused with that from a short GRB source? How do we differentiate between the different sources in noisy detector data? To answer some of these questions, we use maximum entropy analysis for a network of gravitational-wave detectors, such as LIGO or VIRGO, and recover simulated burst waveforms from noisy data. The efficiency with which we recover the waveforms is computed by cross-correlating with simulated core-collapse and merger waveforms. We also estimate how strong a gravitational-wave signal needs to be, before we can distinguish between different types of progenitors. [Preview Abstract] |
Monday, May 4, 2009 3:06PM - 3:18PM |
R11.00009: Using Gravitational Wave Pulsar Observations to measure electron column density Shane Larson, Seth Timpano For binaries whose sky position, orientation, and chirp mass ${\cal M}_{c}$ are known, the observed gravitational wave amplitude of the binary system is a direct measure of the distance to the binary. In a similar spirit, the distance to radio pulsars can be inferred from pulsar observations from the dispersion measure, the integrated column density of electrons along the line of sight to a pulsar that causes an observational broadening of a radio pulse. This talk considers a multi-messenger observation of galactic binary systems that contain a pulsar component detectable in the electromagnetic spectrum, and a detectable gravitational wave signal, and demonstrates how the two independent distance measures can be used to measure the electron column density along the line of sight to the pulsar. [Preview Abstract] |
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