Iron needles in supernova remnants? |
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Authors: | Haley L Gomez Loretta Dunne Stephen A Eales Edward L Gomez Michael G Edmunds |
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Institution: | Department of Physics &Astronomy, Cardiff University, 5 The Parade, Cardiff CF24 3YB;School of Physics &Astronomy, University of Nottingham, University Park, Nottingham NG7 2RD;Faulkes Telescope Project, Cardiff University, 5 The Parade, Cardiff CF24 3YB |
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Abstract: | It has been suggested by Dwek that iron needles could explain the submillimetre emission from the Cas A supernova remnant (SNR) with only a very small total mass. We investigate whether a similar model holds for the Kepler SNR, and find that its emission could indeed be explained by a dust mass of less than 10?2 M⊙ , dependent on the axial ratio l / a of the needles – which we constrain to be less than 700. But the implied needle model for Kepler is inconsistent with that suggested for Cas A since either the needles would have to have a resistivity one or two orders of magnitude greater than those in Cas A or the electron density in Kepler's shocked plasma must be 40 times greater than suggested by X-ray observations. An additional problem with the needle model is that the implied thickness of the needles seems to be implausibly small, if the emission properties are calculated under the usual approximations. |
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Keywords: | ISM: supernovae ISM: individual: Kepler extinction submillimetre |
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