ESA Hubble Science Release | 2015 Mar 05
Hubble sees multiple images of a supernova for the very first timeAstronomers using the NASA/ESA Hubble Space Telescope have, for the first time, spotted four images of a distant exploding star. The images are arranged in a cross-shaped pattern by the powerful gravity of a foreground galaxy embedded in a massive cluster of galaxies. The supernova discovery paper will appear on 6 March 2015 in a special issue of Science celebrating the centenary of Albert Einstein’s theory of general relativity.
Whilst looking closely at a massive elliptical galaxy and its associated galaxy cluster MACS J1149+2223 — whose light took over 5 billion years to reach us — astronomers have spotted a strange and rare sight. The huge mass of the galaxy and the cluster is bending the light from a much more distant supernova behind them and creating four separate images of it. The light has been magnified and distorted due to gravitational lensing and as a result the images are arranged around the elliptical galaxy in a formation known as an Einstein cross.
Although astronomers have discovered dozens of multiply imaged galaxies and quasars, they have never before seen multiple images of a stellar explosion. ...
This unique observation will help astronomers refine their estimates of the amount and distribution of dark matter in the lensing galaxy and cluster. There is more dark matter in the Universe than visible matter, but it is extremely elusive and is only known to exist via its gravitational effects on the visible Universe, so the lensing effects of a galaxy or galaxy cluster are a big clue to the amount of dark matter it contains.
When the four supernova images fade away as the explosion dies down, astronomers will have a rare chance to catch a rerun of the explosion. The supernova images do not arrive at the Earth at the same time because, for each image produced, the light takes a different route. Each route has a different layout of matter — both dark and visible — along its path. this causes bends in the road, and so for some routes the light takes longer to reach us than for others. Astronomers can use their model of how much dark matter is in the cluster, and where it is, to predict when the next image will appear as well as using the time delays they observe to make the mass models even more accurate. ...
Multiple Images of a Highly Magnified Supernova Formed by an Early-Type Cluster Galaxy Lens - Patrick L. Kelly et al
- Science 347(6226) 1123 (06 Mar 2015) DOI: 10.1126/science.aaa3350
arXiv.org > astro-ph > arXiv:1411.6009 > 21 Nov 2014 (v1), 24 Nov 2014 (v2)
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