GW170814

GW170814: two black holes merging about 610 Mpc away, localized to 87 square degrees at 90%.

Arrived

2017-08-14

What merged

two black holes

Distance

610 ± 230 Mpc

50% credible region

16.3 square degrees

90% credible region

86.6 square degrees

The first wave heard by three detectors. Virgo had joined the two LIGO sites a fortnight before, and the difference is this outline: two black holes of about thirty and twenty-five solar masses, 610 Mpc away, pinned to 87 square degrees. With LIGO alone the region was over a thousand square degrees — a third instrument, and a third arrival time, cut it to this. Nothing was seen in light and nothing was expected: black holes merging give off none.

Those two areas are credible regions rather than a boundary: the smaller holds half the probability and the larger nine tenths, and the tenth left over really is outside it. There is no right ascension and declination here because there is none to give — open it in the app to see the patch itself.

GWTC-1 sky localization for GW170814 — LIGO Scientific Collaboration and Virgo Collaboration

Open it in Bhagol — opens the app if you have it, and this page if you do not.