A supernova and its host galaxy are the subject of today’s NASA/ESA Hubble Space Telescope Picture of the Week. The galaxy in question is LEDA 132905, which is situated in the constellation Sculptor. Even at over 400 million light-years away, LEDA 132905’s spiral structure is faintly visible, as are patches of bright blue stars.
The bright white dot directly in the centre of the image, between the bright centre of the galaxy and its faint left edge, is a supernova named SN 2022abvt. SN 2022abvt was discovered in late 2022, and Hubble observed the explosion about two months later. This image was constructed from data collected to study Type Ia supernovae, which occur when the exposed core of a dead star ignites in a sudden, destructive burst of nuclear fusion. Researchers are interested in this type of supernova because they can be used to measure precise distances to other galaxies.
The Universe is a big place, and supernova explosions are fleeting. How is it possible to be in the right place at the right time to catch a supernova when it happens? Today, most supernovae are discovered by robotic telescopes that continuously scan the night sky. But some are still found the old-fashioned way, by careful observers who take repeated images of the sky and search for changes. SN 2022abvt was spotted by the Asteroid Terrestrial-impact Last Alert System, or ATLAS. As the name suggests, ATLAS was designed to track down the faint, fast-moving signals from asteroids close to Earth. In addition to searching out asteroids, ATLAS also keeps tabs on objects that brighten or fade suddenly, like supernovae, variable stars and galactic centres powered by hungry black holes.
[Image Description: In the exact centre a supernova is seen as a small but bright blue dot. It lies atop a spiral galaxy, close to the glowing centre and next to some bright patches of blue stars in the galaxy. A small number of more minor galaxies are visible around the comparatively large spiral as small glowing discs, while further distant galaxies are seen as mere orangish spots and smudges, all on a black background.]