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

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

The Soft Gamma-Ray Repeaters appear to be a completely new manifestation of neutron stars. SGR 1806-20 and SGR 1900+14 may have highly unusual stellar counterparts, whose spectra peak in the far infrared. They have not been detected at submillimeter or millimeter wavelengths. 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. Their spectra are inconsistent with monoenergetic synchrotron and black body radiation models, but are consistent with simple dust models. We briefly review here our latest millimeter, submillimeter, and infrared observations. We include new upper limits at 235 GHz (1.3 mm) for SGR 1806-20 and SGR 0525-66. The extended IRAS emission detected for SGR 0525-66 is consistent with that expected from heated dust in the supernova remnant N49. Here we show a preliminary analysis of our recent 9.862 micron imaging of the region around SGR 0525-66. We do not detect any point sources, at flux limits lower than would be expected if the other two SGR were placed at the distance of the LMC.

Status: Advances in Space Research, 22, 1133. Final draft: 980413 available.

Download gzipped postscript file.