AsianScientist (Jun. 17, 2019) – By combining one of the world’s most powerful digital cameras and a telescope capable of capturing a wider shot of the night sky compared to other big telescopes, a team of researchers from Japan has identified approximately 1,800 new supernovae. Their findings are published in the Publications of the Astronomical Society of Japan.
A supernova is the name given to an exploding star that has reached the end of its life. The star often becomes as bright as its host galaxy, shining one billion times brighter than the sun for anytime between a month to six months before dimming down. Supernova classed as Type Ia are useful because their constant maximum brightness allows researchers to calculate how far the star is from Earth.
In recent years, researchers began reporting a new type of supernovae 5-10 times brighter than Type Ia supernovae, named super luminous supernovae. Their unusual brightness enables researchers to spot stars in the farthest parts of the universe usually too faint to observe.
But supernovae are rare events, and there are only a handful of telescopes in the world capable of capturing sharp images of distant stars. In order to maximize the chances of observing a supernova, a team led by Professor Naoki Yasuda at the Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU), Japan, used the Subaru Telescope—capable of generating sharp stellar images—with the Hyper Suprime-Cam, an 870 megapixel digital camera attached at its top, to capture a very wide area of the night sky in one shot.
By taking repeated images of the same area of night sky over a six-month period, the researchers could identify new supernovae by looking for stars that suddenly appeared brighter before gradually fading out. As a result, the team identified five super luminous supernovae and about 400 Type Ia supernovae.
Fifty-eight of these Type Ia supernovae were located more than eight billion light years away from Earth. In comparison, it took researchers using the Hubble Space Telescope about ten years to discover a total of 50 supernovae located more than eight billion light years away from Earth.
“The Subaru Telescope and Hyper Suprime-Cam have already helped researchers create a 3D map of dark matter and observe primordial black holes. But now, this result proves that this instrument has a very high capability for finding supernovae very, very far away from Earth,” said Yasuda.
The article can be found at: Yasuda et al. (2019) The Hyper Suprime-Cam SSP Transient Survey in COSMOS: Overview.
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Source: Kavli Institute for the Physics and Mathematics of the Universe; Photo: Yasuda et al.
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