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On 2019 April 25 , the LIGO Livingston detector observed a compact binary coalescence with signal-to-noise ratio 12.9 .
The Virgo detector was also taking data that did not contribute to detection due to a low signal-to-noise ratio , but were used for subsequent parameter estimation .
The 90 % credible intervals for the component masses range from 1.12 to 2.52 \mathit { M _ { \odot } } ( 1.45 to 1.88 \mathit { M _ { \odot } } if we restrict the dimensionless component spin magnitudes to be smaller than 0.05 ) .
These mass parameters are consistent with the individual binary components being neutron stars .
However , both the source-frame chirp mass 1.44 _ { -0.02 } ^ { +0.02 } \mathit { M _ { \odot } } and the total mass 3.4 _ { -0.1 } ^ { +0.3 } { \mathit { M _ { \odot } } } of this system are significantly larger than those of any other known binary neutron star system .
The possibility that one or both binary components of the system are black holes can not be ruled out from gravitational-wave data .
We discuss possible origins of the system based on its inconsistency with the known Galactic binary neutron star population .
Under the assumption that the signal was produced by a binary neutron star coalescence , the local rate of neutron star mergers is updated to 250 – 2810 { Gpc ^ { -3 } { yr } ^ { -1 } } .