The optical afterglow of the short gamma-ray burst associated with GW170817

Understand

The binary neutron star merger GW170817 was the first multi-messenger event observed in both gravitational and electromagnetic waves.

• The electromagnetic signal began approximately 2 seconds post-merger with a weak, short burst of gamma-rays, which was followed over the next hours and days by the ultraviolet, optical and near-infrared emission from a radioactively- powered kilonova.
• Later, non-thermal rising X-ray and radio emission was observed.
• The low luminosity of the gamma-rays and the rising non-thermal flux from the source at late times could indicate that we are outside the opening angle of the beamed relativistic jet.