Gravitational Radiation, Inspiraling Binaries, and Cosmology
Abstract
We show how to measure cosmological parameters using observations of inspiraling binary neutron star or black hole systems in one or more gravitational wave detectors. To illustrate, we focus on the case of fixed mass binary systems observed in a single Laser Interferometer Gravitationalwave Observatory (LIGO)like detector. Using realistic detector noise estimates, we characterize the rate of detections as a function of a threshold signaltonoise ratio $\rho_0$, the Hubble constant $H_0$, and the binary ``chirp'' mass. For $\rho_0 = 8$, $H_0 = 100$ km/s/Mpc, and $1.4 \msun$ neutron star binaries, the sample has a median redshift of $0.22$. Under the same assumptions but independent of $H_0$, a conservative rate density of coalescing binaries ($8\times10^{8}\,{\rm yr}^{1}\,{\rm Mpc}^{3}$) implies LIGO will observe $\sim 50\,{\rm yr}^{1}$ binary inspiral events. The precision with which $H_0$ and the deceleration parameter $q_0$ may be determined depends on the number of observed inspirals. For fixed mass binary systems, $\sim 100$ observations with $\rho_0 = 10$ in the LIGO detector will give $H_0$ to 10\% in an EinsteinDeSitter cosmology, and 3000 will give $q_0$ to 20\%. For the conservative rate density of coalescing binaries, 100 detections with $\rho_0 = 10$ will require about 4~yrs.
 Publication:

The Astrophysical Journal
 Pub Date:
 July 1993
 DOI:
 10.1086/186898
 arXiv:
 arXiv:grqc/9304020
 Bibcode:
 1993ApJ...411L...5C
 Keywords:

 Binary Stars;
 Cosmology;
 Gravitational Effects;
 Neutron Stars;
 Computational Astrophysics;
 Maximum Likelihood Estimates;
 Red Shift;
 Stellar Orbits;
 Astrophysics;
 COSMOLOGY: DISTANCE SCALE;
 COSMOLOGY: THEORY;
 GRAVITATION;
 METHODS: STATISTICAL;
 STARS: BINARIES: CLOSE;
 General Relativity and Quantum Cosmology;
 Astrophysics
 EPrint:
 13 pages (plus 1 figure), LaTeX/aasms, NUGR4