The brightening of the pulsar wind nebula of PSR B0540-69 after its spin-down-rate transition
Abstract
It is believed that an isolated pulsar loses its rotational energy mainly through a relativistic wind consisting of electrons, positrons and possibly Poynting flux1-3. As it expands, this wind may eventually be terminated by a shock, where particles can be accelerated to energies of X-ray synchrotron emission, and a pulsar wind nebula (PWN) is usually detectable surrounding a young energetic pulsar1-3. However, the nature and/or energetics of these physical processes remain very uncertain, largely because they typically cannot be studied in a time-resolved fashion. Here we show that the X-ray PWN around the young pulsar PSR B0540-69 brightens gradually up to 32 ± 8% over the mean previous flux, after a sudden change in the spin-down rate of 36% in December 2011. This spin-down-rate transition has very different properties from a traditional pulsar glitch4. No evidence is seen for any change in the pulsed X-ray emission. We conclude that the spin-down-rate transition results from a sudden change in the pulsar magnetosphere that increases the pulsar wind power and hence the PWN X-ray emission. The X-ray light curve of the PWN suggests a mean lifetime of the particles of 397 ± 374 d, corresponding to a magnetic field strength of 0.7 8-0.28+4.50mG ? in the PWN.
- Publication:
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Nature Astronomy
- Pub Date:
- August 2019
- DOI:
- 10.1038/s41550-019-0853-5
- arXiv:
- arXiv:1909.04364
- Bibcode:
- 2019NatAs...3.1122G
- Keywords:
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- Astrophysics - High Energy Astrophysical Phenomena
- E-Print:
- 17 pages, 2 figures