A long time ago, in a galaxy far far away, two neutron stars merged

Published on October 18, 2017 by Allison Horne  

For the first time ever, scientists have been able to detect both the first light aftermath and gravitational wave emission resulting from two merging neutron stars! The two stars from the NGC 4993 galaxy were detected by NASA’s Fermi Gamma-ray Space Telescope that captured the light from their explosion a few days after their gravitational-waves were observed by the National Space Foundation’ Laser Interferometer Gravitational-wave Observatory (LIGO). LIGO in the past has detected four, possibly five, other gravitational-wave events, but none of them have resulted from the merging of two neutron stars!

The two neutron stars circled each other with increasing speed until their eventual collision, which is known as a kilonova. The collision resulted in a slew of metallic and radioactive debris, a surprise UV (ultra violet) light emission, and a jet stream of X-ray emission. Paul Hertz, director of NASA’s Astrophysics Division at the agency’s headquarters in Washington, comments, “Now, for the first time, we’ve seen light and gravitational waves produced by the same event. The detection of a gravitational-wave source’s light has revealed details of the event that cannot be determined from gravitational waves alone.” This event is especially important not only because it has confirmed all of our previous theories about this type of gravitational-wave event and is the first ever neutron star on neutron star collision observed, but because it has opened an incredible amount of venues for new research and exploration. For more information on gravitational-wave events and neutron star kilonovas, explore the link below!


Animation credits: NASA's Goddard Space Flight Center/CI Lab