First ever supernova found using adaptive optics

An international team of astronomers, led by Seppo Mattila (now based at Tuorla Observatory) have found the first supernova using adaptive optics techniques. The supernova, called SN 2004ip, was discovered using the Naos Conica Adaptive Optics instument on the European Southern Observatory's Very Large Telescope (VLT), one of the world's most powerful. In addition to Seppo Mattila a number of scientists were involved in the project, including Petri Väisänen (Southern African Astronomical Observatory). Supernovae are stars which undergo violent explosion at the end of their lives, releasing huge amounts of energy, which can lead them to outshine even their host galaxies for a short time.

The number of supernovae discovered at infrared wavelengths is still very small, in fact, before SN 2004ip only half a dozen of the many thousands of known supernovae had been found in the infrared.

The image on the left shows the luminous infrared galaxy IRAS 18293-3413, taken with the adative optics system at the Very Large Telescope in Chile in May 2004. The image on the right, taken in September 2004, shows a faint (due to heavy obscuration by dust) new source, a supernova, now given the name SN2004ip. The position of the supernova has been marked with red tick marks. You may need to see the larger version of this image.

Working in the infrared has particular advantages, because it allows one to probe past the dust which can effectively obscure even the brightest supernovae at visible wavelengths. Certain types of galaxies, particularly those undergoing rapid star formation ("starburst"), can have particularly high amounts of dust, and finding supernovae in such galaxies has been a great challange. Adaptive Optics offer a path forward, because the technique provides greatly improved images of such galaxies, with much finer details being seen. Adaptive Optics in the infrared thus offers many improvements in the hunt for supernovae in luminous and ultraluminous infrared galaxies. Despite the large rate at which supernova are expected to occur, to date only a handful of supernovae have been found in these galaxies and those mostly at radio wavelengths.

The introduction of adaptive optics at the Very Large Telescope and other 8 meter class telescopes, now enables near-infrared searches for supernovae at a spatial resolution comparable to typical radio studies. After the pioneering discovery of SN 2004ip in IRAS 18293-3413, the number of supernovae discovered in luminous infrared galaxies is likely to increase rapidly thanks to the availability of adative optics correction on 8 meter class telescopes.

Adaptive optics imaging of a more distant luminous infrared galaxy IRAS 19115-2124 did not reveal any supernovae. However, the combination of the superb images from VLT with data from the Spitzer and Hubble Space Telescopes and from the 10 meter class South African Large Telescope allowed the team to study this multiple merger system (dubbed "the Bird") in extraordinary detail. The system appears to be the collision of two spiral galaxies and a third irregular galaxy.

Seppo Mattila has started working at Tuorla Observatory from August 2007, as an Academy of Finland Researcher.

"The Bird" galaxy (or IRAS 19115-2124) appears to be the collision of two spiral galaxies and a third irregular galaxy.

The supernova study has been published in the Astrophysical Journal, and the preprint is available here.

The study of "The Bird" has been submitted to the Monthly Notices of the Royal Astronomical Society, and the preprint is available here.