Supernova Split into Four Images by Cosmic Lens

W. M. Keck Observatory press release

Astronomers have for the first time spotted four images of a distant exploding star, arranged in a cross-shape pattern by a powerful gravitational lens. In addition to being a unique sighting, the discovery will provide insight into the distribution of dark matter. The findings will appear March 6 in a special issue of the journal Science, celebrating the centenary of Albert Einstein’s Theory of General Relativity.

This image shows the light of a supernova split into four images by a foreground elliptical galaxy embedded in a giant cluster of galaxies. The four images were spotted on Nov. 11, 2014. Credit: NASA/ESA
Two teams spent a week analyzing the object’s light, confirming it was the signature of a supernova, then turned to the W. M. Keck Observatory on Mauna Kea, in Hawaii, to gather critical measurements including determining the distance to the supernova’s host galaxy 9.3 billion light-years from Earth.

To explain the unique, four-up projection, the scientists determined a galaxy cluster and one of its massive elliptical members are gravitationally bending and magnifying the light from the supernova behind it, through an effect called gravitational lensing. First predicted by Albert Einstein, this effect is similar to a glass lens bending light to magnify and distort the image of an object behind it. The multiple images, arranged around the massive elliptical galaxy, form an Einstein Cross, a name originally given to a multiple-lensed quasar that appear as a cross.

Although astronomers have discovered dozens of multiply imaged galaxies and quasars, they have never seen a stellar explosion resolved into several images. “It really threw me for a loop when I spotted the four images surrounding the galaxy – it was a complete surprise,” said Patrick Kelly of the University of California, Berkeley, lead author of the paper and a member of the Grism Lens Amplified Survey from Space (GLASS) collaboration. The GLASS group is working with the FrontierSN team to analyze the supernova.

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Hubble and Keck Unveil a Deep Sea of Small and Faint Early Galaxies

W. M. Keck Observatory press release

A team of scientists led by astronomers at the University of California, Riverside has used NASA’s Hubble Space Telescope and the W. M. Keck Observatory to uncover the long-suspected underlying population of galaxies that produced the bulk of new stars during the universe’s early years.

Galaxy Cluster Abell 1689
Galaxy Cluster Abell 1689 Credit: HST/STScI, H. Ford (JHU)
The galaxies are the smallest, faintest, and most numerous galaxies ever seen in the remote universe, and were captured by Hubble deep exposures taken in ultraviolet light, and confirmed using the mighty Keck I telescope on the summit of Mauna Kea on the island of Hawaii.

Study results appear in the Jan. 10 issue of The Astrophysical Journal, and will be presented today (Jan. 7) at the 223rd meeting of the American Astronomical Society in Washington DC.

The 58 young, diminutive galaxies spied by Hubble were photographed as they appeared more than 10 billion years ago, during the heyday of star birth.

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