While nearby supernovae are bright enough for even amateur astronomers to spy, these farthest ones require more specialized equipment. Subaru, which is run by the National Astronomical Observatory of Japan, has a mirror 8.2 meters (27 feet) across, allowing it to peer into the distant universe to spy dim objects. For this study, researchers used its Hyper Suprime-Cam, a 3-ton camera taller than a person to capture the 1,824 supernovae that make up the collection.
The new supernovae are identified in a paper led by Naoki Yasuda from the Kavli Institute for the Physics and Mathematics of the Universe and published May 30 in the Publications of the Astronomical Society of Japan.
Supernova Super-study
Among the collection are a special type of stellar explosion called Type Ia supernovae. Type Ia supernova are special because they always explode at the same luminosity, or intrinsic brightness. By measuring how bright they appear to Earthly eyes or telescopes, astronomers can judge how far away the explosion occurred, since more distant supernova will appear dimmer than closer ones. For this reason, they are highly valued as “standard candles,” a way to measure distance in the cosmos. The farthest sources also offer information about the expansion rate of the universe, which has recently come under question again.
It took the Hubble Telescope nearly a decade to discover 50 of these Type Ia supernovae more distant than 8 billion light-years. Now, in just two years of observing between 2016 and 2017, the Subaru Telescope captured 58.
