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GW240921_201835 | Gravitational-wave mergers | Apex Andromeda | Apex Andromeda

Black Holes/Gravitational-wave mergers/GW240921_201835

ConfirmedBinary Black Hole

GWOSC compact-binary event

GW240921_201835

Both component-mass lower bounds exceed 3 solar masses

Primary mass34.9 M☉

Secondary mass9.8 M☉

ObservedSep 21, 2024

Event identity

Classification and release

ID: gwtc:GW240921_201835
Event name: GW240921_201835
Classification: Binary Black Hole
Composition status: Confirmed
Confidence boundary: Both component-mass lower bounds exceed 3 solar masses
Catalog: GWTC-5.0
Preferred event version: v1
Observed at: Saturday, September 21, 2024 at 8:18:35 PM UTC UTC
GPS time: 1,410,985,133.8

Source-frame posterior

Component and remnant masses

Primary mass: 34.9 (-9.4, +8.9) M☉
Secondary mass: 9.8 (-1.7, +3) M☉
Remnant mass: 43.7 (-7.2, +7.6) M☉
Effective spin: Not reported by GWOSC
Network SNR: 11.3

Propagation

Distance and statistical context

Luminosity distance: 920 (-300, +760) Mpc
Redshift: 0.18
Astrophysical probability: 0.99
False-alarm rate: 0

Provenance

Official source record

GWOSC · GWTC-5.0

GW240921_201835

Last synchronized 9/12/2026, 1:40:20 AM UTC.

JSON record GWOSC event page