GRB 160625B was a bright gamma-ray burst (GRB) detected by NASA's Fermi Gamma-ray Space Telescope on 25 June 2016 and, three minutes later, by the Large Area Telescope.

[1][2][3] This was followed by a bright prompt optical flash, during which variable linear polarization was measured.

[4] This was the first time that these observations were made when the GRB was still bright and active.

[5] The source of the GRB was a possible black hole, within the Delphinus constellation,[6] about 9 billion light-years (light travel distance) away (a redshift of z = 1.406).

[8] The burst lasted over 11 minutes (680 s),[9][10] and is one of the most energetic bursts ever recorded.