While there is a small chance this is simply due to chance, it looks like the gamma ray burst was triggered by the merging black holes.
Rumor Weed
Yesterday there was a flurry of news about a gamma ray burst (GRB) appearing in the Andromeda galaxy. This would make it the closest observed gamma ray burst, which would be a boon for astronomers. News of this discovery travelled fast, particularly on Twitter and other social networks. Pretty soon a few news sites had picked up the story. But it turns out it wasn’t a gamma ray burst.
Beyond the Farthest Star
When you look up into the night sky, you are seeing into the past. Cosmic distances are so vast that it takes time for light to travel them. The brightest star in the night sky is Sirius, more than 8 light-years away, which means we see Sirius not as it is now, but as it was 8 years ago.