Bulletin of the American Physical Society
APS April Meeting 2014
Volume 59, Number 5
Saturday–Tuesday, April 5–8, 2014; Savannah, Georgia
Session H15: Gravitational Wave Astrophysics III |
Hide Abstracts |
Chair: Ian Harry Room: 103 |
Sunday, April 6, 2014 8:30AM - 8:42AM |
H15.00001: Mis-modelling in Gravitational Wave Astronomy: The Trouble with Templates Laura Sampson, Neil Cornish, Nicolas Yunes Waveform templates are a powerful tool for extracting and characterizing gravitational wave signals. There are, however, attendant dangers in using these highly restrictive signal priors. If strong field gravity is not accurately described by General Relativity (GR), then using GR templates may result in fundamental bias in the recovered parameters, or worse - a complete failure to detect signals. Here we study such dangers, concentrating on three distinct possibilities. First, we show that there exist modified theories compatible with all existing tests that would fail to be detected by the LIGO/Virgo network using searches based on GR templates, but which would be detected using a one parameter post-Einsteinian extension. Second, we study modified theories that produce departures from GR that do not naively fit into the simplest parameterized post-Einsteinian (ppE) scheme. We show that even the simplest ppE templates are still capable of picking up these strange signals and diagnosing a departure from GR. Third, we study how using inspiral-only ppE waveforms for signals that include merger and ringdown can lead to problems in misidentifying a GR departure. We present an easy technique that allows us to self-consistently identify the inspiral portion of the signal. [Preview Abstract] |
Sunday, April 6, 2014 8:42AM - 8:54AM |
H15.00002: A sparse representation of gravitational waves from precessing compact binaries Jonathan Blackman, Bela Szilagyi, Chad Galley, Manuel Tiglio With the advanced generation of gravitational wave detectors coming online in the near future, there is a need for accurate models of gravitational waveforms emitted by binary neutron stars and/or black holes. Post-Newtonian approximations work well for the early inspiral and there are models covering the late inspiral as well as merger and ringdown for the non-precessing case. While numerical relativity simulations have no difficulty with precession and can now provide accurate waveforms for a broad range of parameters, covering the $7$ dimensional precessing parameter space with $\sim 10^7$ simulations is not feasible. There is still hope, as reduced order modelling techniques have been highly successful in reducing the impact of the curse of dimensionality for lower dimensional cases. We construct a reduced basis of Post-Newtonian waveforms for the full parameter space with mass ratios up to $10$ and spins up to $0.9$, and find that for the last $100$ orbits only $\sim 50$ waveforms are needed. The huge compression relies heavily on a reparametrization which seeks to reduce the non-linearity of the waveforms. We also show that the addition of merger and ringdown only mildly increases the size of the basis. [Preview Abstract] |
Sunday, April 6, 2014 8:54AM - 9:06AM |
H15.00003: Bayesian Inference for Transient Gravitational Waves and Instrument Glitches: Theory Neil Cornish, Tyson Littenberg A central challenge in Gravitational Wave Astronomy is identifying weak signals in the presence of non-stationary and non-Gaussian noise. This requires good models for both the signals and the noise. When accurate signal models are available, such as for binary Neutron star systems, it is possible to make robust detection statements even when the noise is poorly understood. In contrast, searches for ``un-modeled'' burst signals are strongly impacted by the methods used to characterize the noise. I will describe a Bayesian approach to the problem that employs a multi-component, variable dimension, parameterized noise and signal model that explicitly accounts for non-stationarity and non-Gaussianity in data from interferometric gravitational wave detectors. [Preview Abstract] |
Sunday, April 6, 2014 9:06AM - 9:18AM |
H15.00004: Bayesian Inference for Gravitational Wave Transients and Instrument Glitches: Applications Tyson Littenberg, Neil Cornish, Vicky Kalogera Optimally identifying and characterizing gravitational wave signals requires accurate models for both the signal and the noise. We have developed a pair of tools, BayesLine and BayesWave, that work together to reliably extract signals from either compact binary mergers or un-modeled bursts of gravitational waves from the non-stationary and non-Gaussian noise of the LIGO instruments. BayesLine dynamically estimates the power spectrum of the Gaussian component of the noise, including the many line features, while BayesWave models noise transients (glitches) and, in the absence of template waveforms, gravitational wave bursts. The effectiveness of this novel approach is demonstrated on data from LIGO's sixth science run. [Preview Abstract] |
Sunday, April 6, 2014 9:18AM - 9:30AM |
H15.00005: Detecting and charactezing black hole binary mergers without waveform templates Margaret Millhouse, Neil Cornish, Tyson Littenberg LIGO/Virgo searches for transient gravitational waves are conventionally divided into two classes - ``un -modeled'' burst searches and template based searches. But these are just two extremes in a continuum of possibilities that depend on the strength of our prior knowledge of the signals. The BayesWave algorithm is a flexible approach to gravitational wave data analysis that is able to span the full continuum of models. I will describe how a model of the time-frequency evolution of a binary system can be used as a parameterized signal prior that allows us to detect binary black hole mergers and extract physical properties such as the masses and spins without the need for waveform templates. [Preview Abstract] |
Sunday, April 6, 2014 9:30AM - 9:42AM |
H15.00006: Identification of BBH Merger Phenomenology Through Principal Component Analysis Deirdre Shoemaker, James Clark, Laura Cadonati, Ik Siong Heng, Nicholas Mangini, Larne Pekowsky Recent years have seen dramatic progress in numerical simulations of the coalescence of binary black hole systems. However, the simulation of highly asymmetric, spinning systems and the construction of accurate inspiral-merger-ringdown physical templates remains challenging. Furthermore, the solution of the inverse problem of parameter estimation in such a high dimensional space, even using recently developed stochastic Bayesian analyses, is extremely computationally expensive. In addition to the full parameter estimation solution using phenomenological templates and physical parameters, it would be informative to have a prompt, robust and automatic indication of whether the signal exhibits evidence for various generic features such as precessional modulation or the presence of higher-order mode content. One possible approach here is to form catalogues of numerical relativity waveforms with distinct physical effects such as this and determine the relative probability that a given GW signal lies in each catalogue. We introduce, and report on the development of, an algorithm designed to perform this task for ``burst-like'' (i.e., merger-ringdown dominated) waveforms via principal analysis of waveform catalogues and the use of nested sampling to perform Bayesian model selection. [Preview Abstract] |
Sunday, April 6, 2014 9:42AM - 9:54AM |
H15.00007: Burst Searches for Compact Binary Coalescences Sergey Klimenko Compact Binary coalescences (CBC) are the most promising sources of gravitational waves (GW) for the first detection with advanced GW detectors. Being the most efficient GW emitters among anticipated GW sources, they are also well understood theoretically in the framework of General Relativity. In the talk I'll discuss different flavors of CBC sources and two types of search methods employed in the GW data analysis: template and excess power. While template methods are the most optimal for CBC sources, I will concentrate on the excess power methods, which are typical for searches of generic GW transients (bursts). How to use burst searches for CBC sources? Why would we do this? What can we learn about CBC sources from a burst search? - these and other questions will be discussed in the talk. [Preview Abstract] |
Sunday, April 6, 2014 9:54AM - 10:06AM |
H15.00008: Search for Gravitational Waves from Eccentric Binary Black Holes Vaibhav Tiwari, Sergei Klimenko Searches for compact binaries assume them to have circular orbits by the time the emitted gravitational radiation enter the frequency range of ground-based detectors. However such systems could also be produced through other channels, like dynamical interaction in galactic nuclei, when a significant fraction of formed binaries may maintain high eccentricities throughout their lifetime. These binaries have unique gravitational wave signatures and are not captured efficiently by searches designed for circular systems. We discuss this promising source of gravitational wave radiation and outline detection strategies with the initial and advanced ground-based detectors. [Preview Abstract] |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700