| Event type | Gravitational wave |
|---|---|
| Instrument | LIGO, Virgo interferometer |
| Distance | 159+69 −71 Mpc |
| Progenitor | Unknown |
GW190425 was a gravitational wave detected [1] on 25 April 2019 at LIGO-Livingston. Some low signal-to-noise data from the Virgo interferometer could not be used for detection but was used for parameter estimation. [2] In contrast to GW170817, LIGO-Hanford was offline and did not observe GW190425, and because the Virgo detection was low-confidence, the event is not well-localized in the sky — the 90% confidence zone spans 8284 deg2 (roughly 20% of the sky), while GW170817 was localized to 28 deg2 (about 0.07% of the sky) before its optical counterpart was identified. [2]
GW190425 was a compact binary coalescence with a signal to noise ratio 12.9. [2] No electromagnetic event has been conclusively associated with GW190425; one candidate is FRB 20190425A in the galaxy UGC 10667. [3] The signal could be result of a collision of two neutron stars, a neutron star and a low-mass black hole, or two low-mass black holes [4] with a total mass of 3.4+0.3
−0.1 M☉ and a chirp mass of 1.44+0.02
−0.02 M☉, much heavier than any binary neutron-star system known from radioastronomy observations. [2] The unusual mass has led to several different hypothesis for the origin of the signal. Some examples include: [5] a neutron star might paired with 4-5 M☉ Helium star might undergo common envelope evolution then supernova to produce an unusual binary neutron star, [6] higher mass binary neutron stars may be preferentially created with either high or low magnetic fields explaining the lack of radioastronomy signals, [7] and the possibility that the mass observation is at the extreme of a distribution characteristic of binary neutron stars. [8]