Hubble Pinpoints Location Of Record-breaking Cosmic Explosion
Peering across 7.5 billion light-years
and halfway back to the Big Bang, NASA's Hubble Space Telescope has photographed
the fading optical counterpart of a powerful gamma ray burst that holds
the record for being the intrinsically brightest naked-eye object ever seen from
Earth. (Credit: Credit: NASA, ESA, N. Tanvir (University of Leicester), and A.
Fruchter (STScI))
ScienceDaily (Apr. 15, 2008) — Peering across 7.5 billion light-years and
halfway back to the Big Bang, NASA's Hubble Space Telescope has photographed the
fading optical counterpart of a powerful gamma ray burst that holds the record
for being the intrinsically brightest naked-eye object ever seen from Earth.
For nearly a minute this single star was
as bright as 10 million galaxies.
Hubble Wide Field and Planetary Camera 2 (WFPC2) images taken on Monday, April 7
show the fading optical counterpart of the titanic blast. The object
erupted in a brilliant flash of
gamma rays and other electromagnetic radiation at 2:12 a.m. EDT
on March 19, and was detected by
Swift, NASA's gamma ray burst watchdog satellite.
Immediately after the explosion, the gamma ray burst glowed as a dim 5th
magnitude "star" in the spring constellation Bootes. Designated GRB 080319B, the
intergalactic firework has been fading away ever since then.
Hubble astronomers had hoped to see the host galaxy where the burst presumably
originated, but were taken aback that the light from the GRB is still drowning
out the galaxy's light even three weeks after the explosion. This is
particularly surprising because it was such a bright GRB initially.
Previously, bright bursts have tended to fade more rapidly, which fits in to the
theory that brighter GRBs emit their energy in a more tightly confined beam. The
slow fading leaves astronomers puzzling about just where the energy came from to
power this GRB, and makes Hubble's next observations of this object in May all
the more crucial.
Called a long-duration gamma ray burst, such events are theorized to be caused
by the death of a very massive star,
perhaps weighing as much as 50 times our Sun. Such explosions, sometimes
dubbed "hypernovae," are more powerful than ordinary supernova explosions and
are far more luminous, in part because their energy seems to be concentrated
into a blowtorch-like beam that, in this case, was aimed directly at Earth.
The Hubble exposure also shows field galaxies around the fading optical
component of the gamma ray burst, which are probably unrelated to the burst
itself.