|THIS IS ONE OF A SERIES OF RELEASES ASSOCIATED WITH THE SODERBERG, ET AL., NATURE PAPER, UNDER EMBARGO THROUGH WEDNESDAY, MAY 21 AT 1 P.M. EDT.
Peter Michaud, (808) 974-2510 (desk); (808) 937-0845 (cell); email@example.com
Gemini Observatory, Hilo, Hawaii
Catching the light of a baby supernova
HILO, Hawaii -- Astronomers have observed the aftermath of spectacular stellar explosions known as supernovae before, but until now no one has witnessed a star dying in real time. While observing supernova 2007uy with the Swift X-ray Telescope, Alicia Soderberg and Edo Berger (Princeton University) discovered a mysterious X-ray flash elsewhere in the galaxy NGC 2770 located about 90 million light years away. Within a few hours observatories around the world scrambled to study its light. In a rapid sequence of events the Gemini North telescope was able to capture and dissect the object's light in a set of optical spectra that contains the earliest spectrum ever obtained of a massive star ending its life in a supernova explosion outside of our galaxy's neighborhood.
"We were in the right place, at the right time, with the right telescope on Jan. 9 and witnessed history," said Soderberg. "Thanks to the unique capabilities of the Swift satellite and the rapid response of the Gemini telescope we were able to observe a star in the act of dying."
The result of this rapid response, following the Jan. 9, 2008 discovery, allowed Gemini to provide time-critical spectroscopic observations of the young supernova and the development of the explosion in a unique sequence of optical spectra using Gemini North telescope on Mauna Kea in Hawaii.
"When I was alerted by Edo Berger shortly after the X-ray outburst, we didn't know what it was," said Jean-René Roy, Deputy Director and Head of Science at the Gemini Observatory. "We immediately agreed to Edo's request for Director's Discretionary time to observe the object." Roy approved the program, "...feeling that we had a unique opportunity."
The spectra were obtained with the Gemini Multi-Object Spectrograph (GMOS) nearly every night between Jan.11-30, 2008 and have set a record for the youngest supernova ever captured by optical spectroscopy other than supernova 1987A which occurred in the satellite galaxy to the Milky Way known as the Large Magellanic Cloud.
"A few weeks later we had accumulated an outstanding sequence of optical spectra of a young supernova. I am very pleased that Gemini could work with the team and play a strategic role in following this unusual event," said Roy.
These data allowed the team to show that this was a Helium-rich supernova of a type known as Ibc, and also to measure the speed of the explosion. The X-ray outburst is interpreted as the break-out of the supernova shock through the dense wind surrounding the progenitor star, suspected to have been what is known as a Wolf-Rayet star.
"We now know what X-ray pattern to look for when a star explodes," said Berger. "Hopefully we will be able to find and study many more supernovae at this critical moment."
The potential of finding a large number of supernovae at the time of explosion will also open up avenues of research that previously seemed nearly impossible. In particular, the determination of the exact explosion time will allow searches for neutrino and gravitational wave bursts that are predicted to accompany the collapse of the stellar core and the birth of the neutron star.
"The next generation of X-ray satellites will find hundreds of supernovae exactly when they explode, and telescopes like Gemini will help us study the detailed physics," said Soderberg. "I am thrilled that our discovery is leading this new wave of astronomy."
The results will be published in the May 22, 2008 issue of the journal Nature by lead author Alicia Soderberg (with 37 co-authors) in a paper titled: "An extremely luminous X-ray outburst marking the birth of a normal supernova."
NOTE: Gemini Observatory is concurrently releasing a high-resolution color image of the galaxy and supernova that this press release is based upon. The image can be downloaded at:
An electronic version of this release with figures can be found at: www.gemini.edu/sn2008d (user and password same as image release above). Both of the above URLs will be password protected until the embargo expires.
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The Gemini Observatory is an international collaboration with two identical 8-meter telescopes. The Frederick C. Gillett Gemini Telescope is located at Mauna Kea, Hawaii (Gemini North) and the other telescope at Cerro Pachón in central Chile (Gemini South), and hence provide full coverage of both hemispheres of the sky. Both telescopes incorporate new technologies that allow large, relatively thin mirrors under active control to collect and focus both optical and infrared radiation from space.
The Gemini Observatory provides the astronomical communities in each partner country with state-of-the-art astronomical facilities that allocate observing time in proportion to each country's contribution. In addition to financial support, each country also contributes significant scientific and technical resources. The national research agencies that form the Gemini partnership include: the US National Science Foundation (NSF), the UK Science and Technology Facilities Council (STFC), the Canadian National Research Council (NRC), the Chilean Comision Nacional de Investigacion Cientifica y Tecnologica (CONICYT), the Australian Research Council (ARC), the Argentinean Consejo Nacional de Investigaciones Científicas y Tecnicas (CONICET) and the Brazilian Conselho Nacional de Desenvolvimento Científico e Tecnologico CNPq). The observatory is managed by the Association of Universities for Research in Astronomy, Inc. (AURA) under a cooperative agreement with the NSF. The NSF also serves as the executive agency for the international partnership.