X-shooter spectra montage of kilonova in NGC 4993

This montage of spectra taken using the X-shooter instrument on ESO's Very Large Telescope shows the changing behaviour of the kilonova in the galaxy NGC 4993 over a period of 12 days after the explosion was detected on 17 August 2017. Each spectrum covers a range of wavelengths from the near-ultraviolet to the near-infrared and reveals how the object became dramatically redder as it faded.