Are the recently observed soft $gamma$-ray bursts from stellar superflares
Reference is made to the recent discovery of gamma -ray bursts having a typical duration of the order of seconds and typical photon energies of the order of hundreds of keV. Predictions of gamma -ray bursts from supernovae have been made, but there are several difficulties in interpreting the observed bursts as originating in supernovae. Such bursts have been observed to occur frequently, with no apparent correlation with observed supernova events. It seems that alternative possibilities for the origin of these bursts should be explored, and it is suggested that the outbursts are giant versions of the x-ray bursts seen in solar flares, to which they bear a strong resemblance in many respects to the solar x-ray bursts recently observed with a 2 sec. time resolution. The time scale is much longer than that predicted for supernovae. The spectral characteristics of the non-solar bursts have been studied in experiments carried by the satellite IMP-6. Multiple-burst events have been observed. It is stated to be plausible that the bursts are caused by the bremsstrahlung of electrons accelerated to high energies in a stellar flare event. The stellar flare hypothesis lends itself to various observational tests. Possible observational features are (1) repetitions of the bursts at the same position; (2) simultaneous radio bursts at the same position; (2) simultaneous radio bursts at the same position; and (3) gamma -ray lines at 0.51 MeV (positron annihilation), 2.23 MeV (n + p -- d + gamma ), 4.4 MeV (/sup 12/C*), and 6.1 MeV (/sup 16/O*), such as have been seen in strong solar flares. These lines may be present because the flare may accelerate protons as well as electrons, so that various nuclear reactions may occur in the flare. If the stellar flare hypothesis is verified it may imply a significant source of galactic low-energy cosmic rays in the solar neighborhood, depending on the frequency and intensity of the flares. (UK)
- Research Organization:
- Goddard Space Flight Center, Greenbelt, MD
- NSA Number:
- NSA-29-016462
- OSTI ID:
- 4384697
- Journal Information:
- Nature (London) Phys. Sci., v. 245, no. 144, pp. 70-71, Other Information: Orig. Receipt Date: 30-JUN-74; Bib. Info. Source: UK (United Kingdom (sent to DOE from))
- Country of Publication:
- United Kingdom
- Language:
- English
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