A Black Hole 'Choir'
Published: July 28, 2016
The blue dots in this field of galaxies, known as the COSMOS field, show galaxies that contain supermassive black holes emitting high-energy X-rays. The black holes were detected by NASA's Nuclear Spectroscopic Array, or NuSTAR, which spotted 32 such black holes in this field and has observed hundreds across the whole sky.
More information: https://www.nustar.caltech.edu/image/nustar160728a