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GW170823 | Gravitational-wave mergers | Apex Andromeda | Apex Andromeda

Black Holes/Gravitational-wave mergers/GW170823

ConfirmedBinary Black Hole

GWOSC compact-binary event

GW170823

Both component-mass lower bounds exceed 3 solar masses

Primary mass38.3 M☉

Secondary mass29 M☉

ObservedAug 23, 2017

Event identity

Classification and release

ID: gwtc:GW170823
Event name: GW170823
Classification: Binary Black Hole
Composition status: Confirmed
Confidence boundary: Both component-mass lower bounds exceed 3 solar masses
Catalog: GWTC-2.1-confident
Preferred event version: v2
Observed at: Wednesday, August 23, 2017 at 1:13:58 PM UTC UTC
GPS time: 1,187,529,256.5

Source-frame posterior

Component and remnant masses

Primary mass: 38.3 (-6.2, +9.5) M☉
Secondary mass: 29 (-7.8, +6.5) M☉
Remnant mass: 63.9 (-6.8, +9.6) M☉
Effective spin: 0.05
Network SNR: 12.2

Propagation

Distance and statistical context

Luminosity distance: 1,970 (-930, +840) Mpc
Redshift: 0.36
Astrophysical probability: Not reported by GWOSC
False-alarm rate: Not reported by GWOSC

Provenance

Official source record

GWOSC · GWTC-2.1-confident

GW170823

Last synchronized 9/12/2026, 3:20:17 AM UTC.

JSON record GWOSC event page