Contents of: VI/111/./abstract/AJCASTRO_SGR_4.abs

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Soft gamma-ray bursts are intense and very brief energetic flashes of celestial
gamma-rays that arise during the erratic activity periods ofmisterious sources:
the Soft Gamma-ray Repeaters (SGRs). They remain as one of the unsolved
problems of modern Astrophysics. Only three SGRs have been detected so far. Two
lie in our galaxy (SGR 1900+14 and SGR 1806-20) and a third one (SGR 0525-66)
in the Large Magellanic Cloud, and was responsible for the famous March 5,1979
event, one of the strongest bursts ever seen so far, which showed a 8.1-s
periodicity during the decline. The two in our Galaxy have been identified at
other wavelenghts. The emission from both SGR 1900+14 and SGR 1806-20 peaks in
the IR. The IR spectra indicates the presence of two components: a point-like
emission peaking at 25 microns and a extended emission dominating at 60 microns
. In particular, SGR 1806-20, is associated with a supernova remnant. Although
a very faint optical counterpart is found at this position, NIR observations
revealed a bright IR object. It belongs to the rare luminous blue variable
class (LBV). Taking into account the distance to the object (about 14.5 kpc),
it seems that this system (the LBV plus the compact object that causes the
bursts) is one of the most luminous in the Galaxy. SGR 1900+14 is also a very
weird system, with a compact object and two supergiants stars forming a triple
system at 12-15 kpc. It has been announced recently (13 Sep 1997, IAUC 6743)
that a new source, (SGR 1814-13) seen first on June 29 and now, again, on 12
September, displays all the characteristics of the soft gamma-ray repeaters,
and would be the 4th of the class, the third in our Galaxy. This is a major
discovery since the discovery of the known repeaters in the late 70's.
Considering that these bursting periods only last a few days, we request here
IR observations with ISO during discretionary time. No IRAS source is detected
within the 10' diameter error box, in contrast with the IRAS detection at the
position of the other two SGRs. The fact that ISO is in orbit provides a unique
opportunity to observe this object, never detected before, in a new window for
potential discovery of the IR counterpart. A new IR source within the
SGR1814-13 area, will give support to the hypothesis that the long-lasting