[Phys-L] additional gravitatonal wave signals

[John Denker <jsd@av8n.com>]

This has been rumored for a while, but has finally passed all checks
and been promoted to an official result:

> LIGO Does It Again: A Second Robust Binary Black Hole Coalescence 
> Observed
>
> News Release • June 15, 2016
>
> The two LIGO gravitational wave detectors in Hanford Washington and 
> Livingston Louisiana have caught a second robust signal from two 
> black holes in their final orbits and then their coalescence into a 
> single black hole. This event was seen on December 26th at 03:38:53
> UTC.

> Like LIGO's first detection, this event was identified within
> minutes of the gravitational wave's passing.  The Boxing Day event
> differed from the LIGO's first gravitational wave observation in some
> important ways, however.

[and so on] 
    https://www.ligo.caltech.edu/news/ligo20160615
    https://www.ligo.caltech.edu/system/media_files/binaries/336/original/press-release.pdf

See also the draft of a scholarly paper:
   "Binary Black Hole Mergers in the first Advanced LIGO Observing Run"
   https://dcc.ligo.org/public/0124/P1600088/015/bbh-o1.pdf