Modeling far-infrared observations of young stellar objects |
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| Authors: | H M Butner G H Moriarty-Schieven M E Ressler M W Werner |
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| Institution: | (1) NASA Goddard Space Flight Center, Code 665, 20771 Greenbelt, MD, USA;(2) USRA, USA |
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| Abstract: | The exotic quantum process of photon splitting  has great potential to explain the softness of emission in soft gamma repeaters (SGRs) if they originate in neutron stars with surface fields above the quantum critical fieldB
cr = 4.413×1013 Gauss. Splitting becomes prolific at such field strengths: its principal effect is to degrade photon energies, initiating a cascade that softens gamma-ray spectra. Uniform field cascade calculations have demonstrated that emission could be softened to the observed SGR energies for fields exceeding about 1014 Gauss. Recently, we have determined splitting attenuation lengths and maximum energies for photon escape in neutron star environments including the effects of magnetospheric dipole field geometry. Such escape energies  esc suitably approximate the peak energy of the emergent spectrum, and in this paper we present results for
esc as a function of photon emission angles for polar cap and equatorial emission regions. The escape energy is extremely insensitive to viewing perspective for equatorial emission, arguing in favour of such a site for the origin of SGR activity. |
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| Keywords: | Soft Gamma Repeaters neutron stars magnetic fields gamma-rays |
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