When is a gravitational-wave signal stochastic?
Abstract
We discuss the detection of gravitational-wave backgrounds in the context of Bayesian inference and suggest a practical definition of what it means for a signal to be considered stochastic—namely, that the Bayesian evidence favors a stochastic signal model over a deterministic signal model. A signal can further be classified as Gaussian-stochastic if a Gaussian signal model is favored. In our analysis we use Bayesian model selection to choose between several signal and noise models for simulated data consisting of uncorrelated Gaussian detector noise plus a superposition of sinusoidal signals from an astrophysical population of gravitational-wave sources. For simplicity, we consider colocated and coaligned detectors with white detector noise, but the method can be extended to more realistic detector configurations and power spectra. The general trend we observe is that a deterministic model is favored for small source numbers, a non-Gaussian stochastic model is preferred for intermediate source numbers, and a Gaussian stochastic model is preferred for large source numbers. However, there is very large variation between individual signal realizations, leading to fuzzy boundaries between the three regimes. We find that a hybrid, transdimensional model comprised of a deterministic signal model for individual bright sources and a Gaussian-stochastic signal model for the remaining confusion background outperforms all other models in most instances.
- Publication:
-
Physical Review D
- Pub Date:
- August 2015
- DOI:
- 10.1103/PhysRevD.92.042001
- arXiv:
- arXiv:1505.08084
- Bibcode:
- 2015PhRvD..92d2001C
- Keywords:
-
- 04.80.Nn;
- 04.30.Db;
- 07.05.Kf;
- 95.55.Ym;
- Gravitational wave detectors and experiments;
- Wave generation and sources;
- Data analysis: algorithms and implementation;
- data management;
- Gravitational radiation detectors;
- mass spectrometers;
- and other instrumentation and techniques;
- General Relativity and Quantum Cosmology;
- Astrophysics - High Energy Astrophysical Phenomena;
- Astrophysics - Instrumentation and Methods for Astrophysics
- E-Print:
- 14 pages, 10 figures