GW170817: a binary neutron star merger

This discovery marks first cosmic event observed in both gravitational waves and light.

GW170817: images of a binary neutron star merger

The images show a numerical simulation representing the binary neutron star coalescence and merger which resulted in the gravitational-wave event GW170817 and gamma ray burst GRB170817A. The two non-spinning neutron stars shown in the animations have 1.528 and 1.222 solar masses and follow the ALF2 equation of state (EOS). The employed parameters (total mass, mass ratio, spin and EOSs) are consistent with the detection made on the 17th of August by the LIGO/Virgo detectors. While only the gravitational wave signal emitted during the inspiral of the two neutron stars has been detected, the detection of electromagnetic counterparts, in particular of the kilonova and gamma ray burst, suggest a complicated evolution of the merger remnant with a possible hypermassive or supramassive neutron star phase and black hole formation as shown in the animation.

Note: Publication of the images requires proper credits and written permission. Please contact the in advance of publication or for higher-resolution versions.

Numerical relativity simulation: T. Dietrich (Max Planck Institute for Gravitational Physics) and the BAM collaboration
Scientific visualization: T. Dietrich, S. Ossokine, H. Pfeiffer, A. Buonanno (Max Planck Institute for Gravitational Physics)

The images below show the two neutron stars and the gravitational waves emitted during the merger.

The images below (snapshots from the movie) show the gravitational wave signal with colors ranging from yellow to red with increasing strength.

The images below (snapshots from the movie) show the density of the neutron stars from light to dark blue with densities in a range of 200 thousand to 600 million tons per cubic centimeter and the matter which gets ejected from the system in purple. This ejected material is the source for the kilonova detected after the neutron star merger. Since the density of this unbound, ejected material is smaller than inside the neutron star, we also show material with densities as low as 600 tons per cubic centimeter. Finally, the black hole that forms after the collapse of the hypermassive neutron star is shown in gray.

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