Summary
V4641 Sagittarii is a system about 20,000 light-years from Earth, in the direction of the constellation Sagittarius. There, a black hole with the mass of about six Suns is slurping material off a giant star of about three solar masses.
The HAWC gamma-ray observatory is designed to pick up high-energy particles streaming in from space. It's made up of 300 big steel tanks, full of purified water. V4641 Sagittarii appeared as an unexpected bright spot of gamma rays.
V4641 Sagittarii was found to be the source of these ultra high-energy gamma rays. Other microquasars have previously been detected throwing off photons at energies of over 25 TeV.
