Chandra X-ray & Hubble Optical Images of GW170817
Astronomers have used Chandra to make the first X-ray detection of a gravitational wave source, which was discovered on August 17, 2017. The X-ray close-ups show both the Chandra non-detection, or upper limit, of X-rays from GW170817 on August 19, and the subsequent detection on August 26, 2017. The full field Hubble image of NGC 4993 shows data obtained on August 22, 2017. This discovery of detecting the aftermath of this gravitational wave event, the first to produce an electromagnetic signal of any type, represents the beginning of a new era in astrophysics.
(Credit: TBD)

GW170817 Schematic
Following the merger of two neutron stars, strong gravitational waves (not shown here) produced the source GW170817. This was followed by a burst of gamma-rays generated by a narrow jet or beam, of high-energy particles, depicted in red. Initially the jet was narrow (shown on the left) with Chandra viewing it from the side, giving an X-ray signal that is too weak to be detected. However, as time passed the material in the jet slowed down and widened (shown on the right) as it slammed into surrounding material, causing the X-ray emission to rise as the jet came into direct view by Chandra. This jet & its counterpart pointed in the opposite direction are likely generated by material falling onto a black hole created by the merger of the two neutron stars. The black hole is located in the white source at the base of the jets.
(Credit: NASA/CXC/K.DiVona)