Recently there was a bright supernova in the galaxy M82. Several members got some really good images of it before it faded.
This type of supernova was a Type-Ia, which means it consisted of binary star system with one member being a white dwarf and the other being a more massive companion star. The white dwarf’s gravity had been pulling material (gas) from the companion star until it reach a critical point and it ignited a runaway thermonuclear explosion on the white dwarf. This incredible outpouring of energy is what makes this type of supernova outshine it’s host galaxy. Astronomers know what type it is by watching the light curve and how fast it fades.