In this discretionary time proposal we request ISO observations of the
recently detected gamma-ray burst (GRB), GRB970111 within the next 4 weeks in
order to search for flaring and/or fading infrared emission associated
with the burst source. Gamma-ray bursts represent one of the great unsolved
mysteries in modern astrophysics. They are intense, energetic flashes of gamma-
rays which occur randomly on the sky at a rate of roughly one per day and which
can last from a few millisec to hundreds of seconds. There is as yet no
unambiguous distance measure to the GRB sources - they may be in an extended
Galactic halo or they  may be at cosmological distances. There is, however, a
growing body of circumstantial evidence favouring a cosmological origin. A
statistical association between GRB error boxes and luminous near-IR galaxies
has been identified. The BeppoSAX X-ray satellite imaged the intense GRB of
January 11, 1997 with its Wide Field Camera,to a precision of 10' radius. The
error box has now been further reduced by triangulation with Ulysses and BATSE
to a strip of size 20'x6'. The rapid availability of such an accurate GRB
location is unprecedented in the history of gamma-ray astronomy and opens a
new window for potential discovery. The fact that ISO is in orbit at this time
provides a unique opportunity to exploit this new capability to the utmost.
The occurrence of such an ideal candidate for observation with ISO could not
have been foreseen at the time of the supplemental call. We therefore propose
to use ISO to raster the 20'x6' error box of GRB970111 within the next
4 weeks, before the target disappears from ISO's view, to search for flaring
and/or fading activity associated with this GRB. Members of this team have
extensive ground-based campaigns already underway to study this GRB at radio
and optical wavelengths. No IR measurements have ever been obtained within
such a short time of the GRB occurrence and no instrument has ever had ISO's
unparalleled capabilities. By using ~3 hours of ISO time for this task, we may
detect that which has eluded a generation of ground-based observers at all
wavelengths i.e. a direct GRB counterpart, which would provide us with both a
distance measure and a burst host.