X-ray & Optical Images of Arp 299
Arp 299 contains two galaxies that are merging, creating a partially blended mix of stars from each galaxy in the process. New data from Chandra reveals 25 bright X-ray sources in Arp 299, and 14 of these are extremely strong emitters of X-rays known as "ultra-luminous X-ray sources," or ULXs. Such a high concentration of ULXs is rare, but caused by the intense star formation resulting from the galactic collision. These images also show data from NuSTAR and Hubble.
(X-ray: NASA/CXC/Univ of Crete/K. Anastasopoulou et al, NASA/NuSTAR/GSFC/A. Ptak et al; Optical: NASA/STScI)