Infrared, Submillimeter, and Millimeter Observations of the Soft Gamma-Ray Repeaters

Smith, I. A., Joyce, R., Schultz, A. S. B., Hurley, K., Vrba, F. J., Hartmann, D., Kouveliotou, C., Van Paradijs, J., Waters, L. B. F. M., Chernin, L. M., Durouchoux, P., Corbel, S., and Wallyn, P.

The Soft Gamma-Ray Repeaters appear to be a completely new manifestation of neutron stars. While a counterpart to SGR 0525-66 has only been detected in X-rays, SGR 1806-20 and SGR 1900+14 have highly unusual stellar counterparts, whose spectra peak in the infrared. Their infrared spectra appear to contain several components: the photospheric emission from star(s) dominates at shorter wavelengths, a bright point source dominates at 25 microns, while an extended source dominates at 60 microns. However, they have not been detected at submillimeter or millimeter wavelengths. The longer wavelength spectra are inconsistent with monoenergetic synchrotron and black body radiation models, but are consistent with simple dust models. We review here our latest millimeter, submillimeter, and infrared observations. We also include a preliminary analysis of higher resolution infrared spectra of SGR 1806-20 and SGR 1900+14 taken recently by the Cryogenic Spectrometer at the Kitt Peak 4-m telescope. These confirm earlier observations that suggested SGR 1806-20 has an outflow, and that the stars comprising the counterpart to SGR 1900+14 have very similar spectra.

Status: 1997, ESA SP-382, ed. C. Winkler, T. J.-L. Courvoisier, and Ph. Durouchoux (Noordwijk: ESA Publications), 191.

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