MAH: The supernova SN 2017 egm was discovered on May 23, 2017 by astronomers at the University of Cambridge. It is located in a spiral galaxy about 420 million light-years away, has a high concentration of elements heavier than hydrogen and helium. It is the first evidence of the appearance of a superluminous supernova in metal for this reason it has been nicknamed Supernova Heavy Metal.