GRB Fireball Persists
Explanation:
It's still there. The
optical counterpart
to the instantly famous
gamma-ray burst (GRB) that
occurred last February 28th
has faded - but not completely. The
astronomical community
had waited patiently for months for the
Earth to proceed far enough along in its
orbit so that the
Sun's glare no longer
ruined inspection of the location of this historic flash. The
above
picture of
GRB 970228, taken September 5th and
released just yesterday, shows an
extended structure in the center that hasn't changed.
However, the arrow indicates a
point on the upper right
that is now
five times dimmer than in preceding months. This
fading point fits a model where the
GRB originated in a
fireball across the universe.
The constant brightness of the extended feature indicates
that it is not reflected emission from the
GRB and might be the
host galaxy. Even so, the
great GRB mystery is not yet over:
for one thing,
how come other GRBs don't appear to occur in galactic hosts?
Authors & editors:
Robert Nemiroff
(MTU) &
Jerry Bonnell
(USRA)
NASA Web Site Statements, Warnings,
and Disclaimers
NASA Official: Jay Norris.
Specific
rights apply.
A service of:
LHEA at
NASA /
GSFC
& Michigan Tech. U.
