Measuring the Spin of Black Holes in Binary Systems Using Gravitational Waves

Author(s)

Vitale, Salvatore ^[1] ; Lynch, Ryan ^[1] ; Veitch, John ^{[2, 3]} ; Raymond, Vivien ^[4] ; Sturani, Riccardo ^{[5, 6]}

Affiliation

^[1] MIT, Cambridge, MA 02138 - USA

^[2] Univ Birmingham, Sch Phys & Astron, Birmingham B15 2TT, W Midlands - England

^[3] NIKHEF H, NL-1098 XG Amsterdam - Netherlands

^[4] CALTECH, LIGO Lab, Pasadena, CA 91125 - USA

^[5] Univ Estadual Paulista, ICTP South Amer Inst Fundamental Res, BR-01104007 Sao Paulo - Brazil

^[6] Univ Estadual Paulista, Inst Fis Teor, BR-01104007 Sao Paulo - Brazil

• Document type: Journal article
• Source: Physical Review Letters; v. 112, n. 25 JUN 25 2014.
• Web of Science Citations: 40

Abstract

Compact binary coalescences are the most promising sources of gravitational waves (GWs) for ground-based detectors. Binary systems containing one or two spinning black holes are particularly interesting due to spin-orbit (and eventual spin-spin) interactions and the opportunity of measuring spins directly through GW observations. In this Letter, we analyze simulated signals emitted by spinning binaries with several values of masses, spins, orientations, and signal-to-noise ratios, as detected by an advanced LIGO-Virgo network. We find that for moderate or high signal-to-noise ratio the spin magnitudes can be estimated with errors of a few percent (5%-30%) for neutron star-black hole (black hole-black hole) systems. Spins' tilt angle can be estimated with errors of 0.04 rad in the best cases, but typical values will be above 0.1 rad. Errors will be larger for signals barely above the threshold for detection. The difference in the azimuth angles of the spins, which may be used to check if spins are locked into resonant configurations, cannot be constrained. We observe that the best performances are obtained when the line of sight is perpendicular to the system's total angular momentum and that a sudden change of behavior occurs when a system is observed from angles such that the plane of the orbit can be seen both from above and below during the time the signal is in band. This study suggests that direct measurement of black hole spin by means of GWs can be as precise as what can be obtained from x-ray binaries. (AU)

• FAPESP's process: 13/04538-5 - Gravitational Wave Research
• Grantee: Riccardo Sturani
• Support Opportunities: Scholarships in Brazil - Young Researchers