April 23, 2013
Distant Type Ia Supernova Magnified Through Gravitational Lensing
Lee Rannals for redOrbit.com — Your Universe Online
Scientists wrote in the Astrophysics Journal Letters they discovered the supernova, PS1-10afx, with the Panoramic Survey Telescope & Rapid Response System 1 (Pan-STARRS1). The supernova exploded over 9 billion years ago, making it a much further object than most studied by Pan-STARRS1.
The supernova stood out from other Pan-STARRS1 objects because it was very red and its brightness changed as fast as normal supernovae. No known physical model helped the team explain how supernova could simultaneously be so luminous, so red and so fast. They found PS1-10afx fits in line with other SNIa, but its observed brightness is far too high for such a distant supernova, leaving gravitational lensing as the only explanation.
Gravitational lensing helps to magnify a distant object in space. While light travels through space in "straight" lines, massive objects warp space and cause rays of light to "bend" around them, helping to magnify that brightness and enabling scientists to observe very distant objects. Thus, if there were a sufficiently massive object aligned between us and PS1-10afx, the supernova would appear brighter.
The object helping to provide the gravitational lensing effect may be detectable after the supernova has faded away, so future observations may be able to provide final confirmation of this scenario.
The team's observations are the first showing a strongly lensed Type Ia supernova. A few years ago, Masamune Oguri, one of the co-authors of the team, predicted Pan-STARRS1 would be capable of discovering strongly lensed SNIa. Now that the team has proven this to be true, next generation surveys with the Hyper Suprime-Cam on the Subaru Telescope and other telescopes can be tuned to discover even more strongly lensed SNIa.
Scientists have used gravitational lensing to help uncover many details about the history of the Universe. In March, scientists making observations with the Atacama Large Millimeter/submillimeter Array (ALMA) telescope say they were able to use this method to see the universe making new stars at its very early stages. Two of the galaxies observed by this group of scientists are the most distant ever seen, one of which started emitting light when the Universe was just a billion years old.
“Only a few gravitationally lensed galaxies have been found before at these submillimetre wavelengths, but now SPT and ALMA have uncovered dozens of them.” said Carlos De Breuck, a member of the team from the European Southern Observatory (ESO). “This kind of science was previously done mostly at visible-light wavelengths with the Hubble Space Telescope, but our results show that ALMA is a very powerful new player in the field.”