Properties of the Binary Black Hole Merger GW150914

TL;DR

This paper analyzes the properties of the first gravitational-wave detection GW150914, revealing details about the merging black holes' masses, spins, distance, and location, confirming the existence of stellar-mass binary black hole systems.

Contribution

It provides the first detailed characterization of a binary black hole merger using gravitational-wave data, including mass, spin, and distance measurements.

Findings

Binary black holes of approximately 36 and 29 solar masses merged.

The resulting black hole has about 62 solar masses.

The source is located roughly 410 Mpc away in the southern hemisphere.

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 $36^{+5}_{-4} M_\odot$ and $29^{+4}_{-4} M_\odot$; 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 $410^{+160}_{-180}$ Mpc, corresponding to a redshift $0.09^{+0.03}_{-0.04}$ 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 $62^{+4}_{-4} M_\odot$ and spin $0.67^{+0.05}_{-0.07}$. This black hole is significantly more massive than any other inferred from electromagnetic observations in the stellar-mass regime.