The Subaru telescope sees 1800 supernovae

Japanese astronomers captured images of an astonishing 1800 supernovae. 58 of these supernovae are type 1a supernovae, of scientific significance, located 8 billion light years from Earth. Type 1a supernovae are known as "standard candles" in astronomy.

The team of astronomers has used the Subaru telescope and one of the most powerful digital cameras in the world to find these supernovae. Astronomers come from the Kavli Institute for Physics and Mathematics of the Universe (IPMU), Tohoku University, Konan University, the National Observatory of Astronomy of Japan and other institutions. The team was led by Professor Naoki Yasuda of IPMU and their findings were published online in the publications of the Astronomical Society of Japan.

A supernova is a star that has reached the end of its life and has exploded brilliantly. Supernovae light up the sky for up to six months and can overshadow their host galaxy. These type 1a supernovae, or classic candles, are particularly useful because of their constant brightness. As their light does not fluctuate much, they are ideal for accurately measuring their distance to the Earth. Standard candles are used to measure the rate of expansion of the universe.

Although the team found 1800 supernovae, including 58 standard candles, it was actually looking for something more elusive.

In recent years, astronomers have reported another type of supernova even brighter than type 1a. These are called Super Luminous Supernovae because they are very bright. They can be up to 10 times brighter than other supernovae and their extreme luminosity allows astronomers to spot them at extreme distances.

This is important because when astronomers look at objects in the far-distant universe, they see the light that left them billions of years ago. Astronomers are turning in the past to the beginnings of the universe. They can look back under the conditions of the primitive universe that allowed these massive first stars to form.

Although this survey revealed 1800 supernovae, there are still rare events. And there are only a few telescopes capable of capturing sharp images. This attempt by the Japanese team used one of these lenses, the Subaru telescope, and combined it with one of the best digital cameras in the world to find these supernovae.

The camera is the Hyper Suprime-Cam (HSC). It's a gigantic camera bigger than a human and is connected to the 8.2-meter Subaru telescope in Maunakea, Hawaii. The Hyper Suprime-Cam camera has an impressive resolution of 870 megapixels.

For six months, Professor Yasuda and his team took repeated images of the same areas of the night sky. Searching for stars that suddenly seemed brighter before fading away, they were able to identify the supernovae.

In total, the team found 1800 supernovae, an astonishing number. (Compare this to the Hubble Space Telescope, which took 10 years to discover 50 supernovae at more than 8 billion light-years away from the Earth.) Of these, 400 were the Type 1a supernova, of which 58 to more than 8 billion light-years from Earth. Even more remarkable, they identified 5 super bright supernovae.

"The Subaru Telescope and Hyper Suprime-Cam have already helped researchers create a 3D map of dark matter and observe primordial black holes, but this result now proves that this instrument has a very high capacity to supernova detection very far from the Earth. . I want to thank all my staff for their time and effort and look forward to analyzing our data to see what kind of image it represents from the universe, "Yasuda said.

Determining the rate of expansion of the universe is one of the overriding goals of astronomy and cosmology. The supernova data from this study will help astronomers clarify their estimate of this rate and will also help them understand the dark energy, the mysterious force at the base of expansion.