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
Instrument
PHT22
Temporal Coverage
1997-10-13T21:45:44Z/1997-10-13T22:41:34Z
Version
1.0
Mission Description
The Infrared Space Observatory (ISO) was the worlds first true orbiting infrared observatory. Equipped with four highly-sophisticated and versatile scientific instruments, it was launched by Ariane in November 1995 and provided astronomers world-wide with a facility of unprecedented sensitivity and capabilities for a detailed exploration of the Universe at infrared wavelengths.
European Space Agency, CASTRO-TIRADO et al., 1998, 'TOO: NEW SOFT GAMMA-RAY REPEATER openParSGR 1814-1340closePar A NEW IR-SOURCEquestionMark', 1.0, European Space Agency, https://doi.org/10.5270/esa-ti0v5hu
