Properties of the Binary Black Hole Merger GW150914

TLDR

This black hole is significantly more massive than any other inferred from electromagnetic observations in the stellar‑mass regime. LIGO detected GW150914 on 14 September 2015, and this study characterizes the source’s properties and parameters. The data around the event were analyzed coherently across the LIGO network using a suite of accurate waveform models that describe gravitational waves from a compact binary system in general relativity. GW150914 was produced by a nearly equal‑mass binary black hole with component masses 36_{‑4}^{+5} M⊙ and 29_{‑4}^{+4} M⊙, a dimensionless spin of the heavier black hole <0.7, a luminosity distance of 410_{‑180}^{+160} Mpc (z ≈ 0.09), a sky location spanning an annulus of 610 deg² in the southern hemisphere, and the merger produced a final black hole of 62_{‑4}^{+4} M⊙ with spin 0.67_{‑0.07}^{+0.05}.

Abstract

On September 14, 2015, the Laser Interferometer Gravitational-Wave Observatory (LIGO) detected a gravitational-wave transient (GW150914); we characterize the properties of the source and its parameters. The data around the time of the event were analyzed coherently across the LIGO network using a suite of accurate waveform models that describe gravitational waves from a compact binary system in general relativity. GW150914 was produced by a nearly equal mass binary black hole of masses 36_{-4}^{+5}M_{⊙} and 29_{-4}^{+4}M_{⊙}; for each parameter we report the median value and the range of the 90% credible interval. The dimensionless spin magnitude of the more massive black hole is bound to be <0.7 (at 90% probability). The luminosity distance to the source is 410_{-180}^{+160} Mpc, corresponding to a redshift 0.09_{-0.04}^{+0.03} assuming standard cosmology. The source location is constrained to an annulus section of 610 deg^{2}, primarily in the southern hemisphere. The binary merges into a black hole of mass 62_{-4}^{+4}M_{⊙} and spin 0.67_{-0.07}^{+0.05}. This black hole is significantly more massive than any other inferred from electromagnetic observations in the stellar-mass regime.