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Media Contact:
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Science and Technology Facilities Council, U.K.
Caught in the act: the Swift satellite observes a supernova explosion in
real-time
Leicester, ENGLAND – U.K. astronomers are part of an international team that has used
the Swift satellite to observe the first moments of a supernova explosion as it happens.
The results are presented in a paper in the journal Nature today (22 May 2008) led by Dr.
Alicia Soderberg of Princeton University. This extraordinarily fortunate discovery led to
multiple observations with other telescopes and allowed the totality of a supernova
explosion to be observed for the first time.
Dr. Kim Page of the University of Leicester, who led the X-ray analysis, said that "this
observation is by far the best example of what happens when a star dies and a neutron
star is born." A typical supernova occurs when the core of a massive star runs out of
nuclear fuel and collapses under its own gravity to form an ultra-dense object known as a
neutron star. The newborn neutron star compresses and then rebounds, triggering a shock
wave that ploughs through the star's gaseous outer layers and blows the star to
smithereens. Theoretical models have long predicted that this shock "break-out" will
produce bright X-ray emission lasting a few minutes but until now the X-ray signal has
never been detected.
Dr. Paul O'Brien, also from the University of Leicester, said "the X-rays from the shock
break out are the earliest electromagnetic radiation that has ever been detected from a
supernova. Understanding supernovae is important as these nuclear furnaces make the
heavy elements from which planets like ours form."
Until this discovery, astronomers have only found supernovae days or weeks later, when
the expanding shell of debris is energized by the decay of radioactive elements forged in
the explosion. Dr. Patricia Schady of the Mullard Space Science Laboratory, University
College London said "Within 2 hours of the burst of X-rays we could see the expanding
ultraviolet fireball with Swift. Telescopes in space and around the world were alerted
well in time to see the radioactive debris as it brightened over the next few days."
The discovery of the first shock breakout can be attributed to luck and Swift's unique
design. On Jan.9, 2008, Swift was observing a supernova known as SN 2007uy in the
spiral galaxy NGC 2770, located 90 million light-years from Earth in the constellation
Lynx. During this observation an extremely bright 5-minute X-ray outburst occurred in
another part of NGC 2770 which was recognized as another supernova occurring while
Swift looked.
In a paper to appear in the May 22 issue of Nature, Soderberg and colleagues show that
the energy and pattern of the X-ray outburst are consistent with a shock wave bursting
through the surface of the progenitor star. This marks the birth of the supernova now
known as SN 2008D.
Although astronomers were lucky that Swift was observing NGC 2770 just at the
moment when SN 2008D's shock wave was blowing up the star, Dr. Mat Page also of the
Mullard Space Science Laboratory, said "Swift is well equipped to study such an event
because of its multiple instruments observing in gamma rays, X-rays, and ultraviolet
light." The X-ray camera and the Ultraviolet-Optical Telescope on Swift were built in the
UK.
Professor Keith Mason, CEO of the Science and Technology Facilities Council which
funds UK involvement with Swift, said "Supernova explosions are taking place all over
the Universe right now, but astronomers can usually only detect them as they grow
brighter after the star has started its violent death. This is a once in a lifetime moment,
where Swift happened to be looking in the right area of the sky and is built to respond
extremely rapidly, so could study supernova SN2008D right from the first moment it
started."
Due to the significance of the X-ray outburst, Soderberg and colleagues immediately
mounted an international observing campaign to study SN 2008D. Observations were
made with major telescopes such as the Hubble Space Telescope, the Chandra X-ray
Observatory, the Very Large Array in New Mexico, the Gemini North telescope in
Hawaii, the Keck I telescope in Hawaii, the 200-inch and 60-inch telescopes at the
Palomar Observatory in California, and the 3.5-meter telescope at the Apache Point
Observatory in New Mexico.
The combined observations helped pin down the energy of the initial X-ray outburst,
which will help theorists better understand supernovae. The observations also show that
SN 2008D is an ordinary Type Ibc supernova, which occurs when a massive, compact
star explodes. Significantly, radio and X-ray observations found no evidence that a jet
played a role in the explosion, ruling out a rare type of stellar explosion known as a
gamma-ray burst.
Swift spends most of its time observing GRBs, but due to its agility can also observe
many other objects each day. This unique capability makes Swift a particularly capable
multi-wavelength observatory.
Swift is a NASA mission in collaboration with the Science Technology and
Facilities Council (STFC) in the UK and the Italian Space Agency (ASI) in Italy. For
more information on Swift, please visit: http://www.swift.ac.uk/.
Notes for Editors:
UK Institutions involved in this result are: University of Leicester, University College
London Mullard Space Science Laboratory and the University of Southampton.
---------------SCIENCE CONTACTS
Dr. Kim Page
Department of Physics & Astronomy
University of Leicester
University Road
Leicester
Phone: 0116 223 1706
Mobile: 07963 990 411
E-mail: kpa@star.le.ac.uk
Dr. Paul O'Brien
Department of Physics & Astronomy
University of Leicester
University Road
Leicester
Phone: 0116 252 5203
Mobile: 07891 894 071
E-mail: pto@star.le.ac.uk
Dr Patricia Schady
Mullard Space Science Laboratory
University College London
Holmbury St. Mary
Dorking RH5 6NT
Phone: 01483 204261
Mobile: 07815 977736
E-mail: ps@mssl.ucl.ac.uk
Dr Mat Page
Mullard Space Science Laboratory
University College London
Holmbury St. Mary
Dorking RH5 6NT
Phone: 01483 204283
E-mail: mjp@mssl.ucl.ac.uk
Dr Tom Maccarone
University of Southampton
tjm@phys.soton.ac.uk
Tel + 44 (0)238059 7548
-------------------------Figures and captions are available from:
https://www.stfc.ac.uk/PMC/PRel/STFC/swift1.htm
Username:: presspolice
Password: presspolice
Supernova_before_labels.jpg
Supernova_before_nolabels.jpg
NASA's Swift satellite took these images of SN 2007uy in galaxy NGC 2770 before SN
2008D exploded. An X-ray image is on the left, the right is in visible light.
Credit: NASA/Swift Science Team/Stefan Immler.
Supernova_after_labels.jpg
Supernova_after_nolabels.jpg
On January 9 Swift caught a bright X-ray burst from an exploding star. A few days later,
SN 2008D appeared in visible light.
Credit: NASA/Swift Science Team/Stefan Immler.
------------------Swift
Launched in November 2004, Swift detects gamma-ray burst and X-ray flashes, and
relays their coordinates to the scientific community within seconds. While Swift rapidly
re-points to continue observations with its high resolution telescopes of the decaying Xray, UV and optical afterglows that accompany these events, rapid follow-up
observations may also be undertaken by other more powerful satellites such as Chandra,
the Hubble Space Telescope or XMM satellites and by the European Southern
Observatory's Very Large Telescope [VLT] and other major observatories. These
powerful co-ordinated observation programmes, instigated by Swift, are slowly
unravelling the mystery of star explosions.
Goddard Space Flight Centre in the US manages Swift, a NASA mission with
participation of the Italian Space Agency [ASI] and the Science and Technology
Facilities Council [STFC] in the United Kingdom.
Swift, a medium-class Explorer mission was built in collaboration with national
laboratories and universities including the Los Alamos National Laboratory, Penn State
University, Sonoma State University, the University of Leicester and University College
London Mullard Space Science Laboratory.
----------------Science and Technology Facilities Council
The Science and Technology Facilities Council ensures the UK retains its leading place
on the world stage by delivering world-class science; accessing and hosting international
facilities; developing innovative technologies; and increasing the socio-economic impact
of its research through effective knowledge exchange partnerships.
The Council has a broad science portfolio including Astronomy, Particle Physics, Particle
Astrophysics, Nuclear Physics, Space Science, Synchrotron Radiation, Neutron Sources
and High Power Lasers. In addition the Council manages and operates three
internationally renowned laboratories:
*
The Rutherford Appleton Laboratory, Oxfordshire
*
The Daresbury Laboratory, Cheshire
*
The UK Astronomy Technology Centre, Edinburgh
The Council gives researchers access to world-class facilities and funds the UK
membership of international bodies such as the European Laboratory for Particle Physics
(CERN), the Institute Laue Langevin (ILL), European Synchrotron Radiation Facility
(ESRF), the European organisation for Astronomical Research in the Southern
Hemisphere (ESO) and the European Space Agency (ESA). It also contributes money for
the UK telescopes overseas on La Palma, Hawaii, Australia and in Chile, and the
MERLIN/VLBI National Facility, which includes the Lovell Telescope at Jodrell Bank
Observatory.
The Council distributes public money from the Government to support scientific
research. Between 2007 and 2008 we will invest approximately 678 million pounds.
The Council is a partner in the UK space programme, coordinated by the British National
Space Centre.
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