LIGO Document T2300195-v1

Estimation of the Stochastic Gravitational Wave Background from binary mergers

Document #:
Document type:
T - Technical notes
Other Versions:
The ground-based international gravitational wave detector network (IGWN), currently including the Laser Interferometer Gravitational wave Observatory (LIGO) stations at Hanford and Livingston, Virgo and KAGRA [1], has detected gravitational waves (GWs) from Compact Binary Coalescence (CBC) sources [2] in distant galaxies as far away as 8 Gigaparsecs [3], which corresponds to a redshift of slightly greater than 1. More distant sources are too faint to be confidently detected as individual events, but are expected to be so numerous that they can be detectable as a Stochastic Gravitational Wave Background (SGWB) [4]. Whilst stringent upper limits on the strength of the SGWB as a function of frequency in units of the cosmological closure density of the universe, Ω_GW(f) [5], have been made through the IGWN, there has been no observed detection of the SGWB as such. However, early implications for the SGWB from the first observation of Binary Black Hole (BBH) mergers [6] and more recent models from advanced LIGO and VIRGO data [7, 8] have all provided estimates of the CBC merger rate that suggest that we are close to detection of the SGWB. The estimates from [6] come from simple simulations of many individual events, while [7] is based on numerical evaluation on an analytical expression for the SGWB. In this project we will reproduce these estimates, through a thorough analysis and study of the methods used by [6, 7] and study the degree to which they agree with each other, as well as look at the extent to which the results depend on uncertainties in the merger rate as a function of mass and redshift distributions of the sources. Overall, this project aims at investigating the predictions on SGWB parameters and constraining its limits, thereby understanding how the background changes due to uncertainties in several important variables. This incorporation of the latest theoretical models, with a key understanding of the limits and constraints in these frameworks, will aid in the long term goal of refining estimates on the SGWB.
Files in Document:
Other Files:

DCC Version 3.4.3, contact Document Database Administrators