Time-dependent modeling of pulsar wind nebulae
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Date
2013Author
Vorster, M.J.
Ferreira, S.E.S.
Tibolla, O.
Kaufmann, S.
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A spatially independent model that calculates the time evolution of the electron spectrum in a spherically expanding pulsar wind nebula (PWN) is presented, allowing one to make broadband predictions for the PWN's non-thermal radiation. The source spectrum of electrons injected at the termination shock of the PWN is chosen to be a broken power law. In contrast to previous PWN models of a similar nature, the source spectrum has a discontinuity in intensity at the transition between the low- and high-energy components. To test the model, it is applied to the young PWN G21.5−0.9, where it is found that a discontinuous source spectrum can model the emission at all wavelengths better than a continuous one. The model is also applied to the unidentified sources HESS J1427−608 and HESS J1507−622. Parameters are derived for these two candidate nebulae that are consistent with the values predicted for other PWNe. For HESS J1427−608, a present day magnetic field of Bage = 0.4 μG is derived. As a result of the small present day magnetic field, this source has a low synchrotron luminosity, while remaining bright at GeV/TeV energies. It is therefore possible to interpret HESS J1427−608 within the ancient PWN scenario. For the second candidate PWN HESS J1507−622, a present day magnetic field of Bage = 1.7 μG is derived. Furthermore, for this candidate PWN a scenario is favored in the present paper in which HESS J1507−622 has been compressed by the reverse shock of the supernova remnant.
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http://hdl.handle.net/10394/13670http://iopscience.iop.org/0004-637X/773/2/139/article
https://doi.org/10.1088/0004-637X/773/2/139