| 15th of June 2020 |
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| ATCA and ACA observations of the pulsar wind nebula of SNR 0540-69.3 |
| by Lundqvist et al. |
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The supernova remnant (SNR) 0540-69.3 in the Large Magellanic Cloud is
believed to be about 1000 years old and to have resulted from the
explosion of a star 20 times more massive than the Sun. The radiation
emitted from the remnant manifests itself mainly through radio and
X-ray emission from a shell of radius 20--35 arcseconds (corresponding
to ∼5--8.5 pc at the 50 kpc distance of LMC). The SNR contains the
50ms pulsar PSR B0540-69.3, with properties very similar to those of
the Crab pulsar.
Like the Crab pulsar, PSR0540 powers a pulsar-wind nebula (PWN) which
is about 7 arcseconds across and has a similar spectral index at radio
wavelengths to other PWN.
Lundqvist et al. have presented observations of the pulsar-wind nebula made with the Atacama Compact Array (ACA) at 2mm and 1.3mm together with the ATCA at 3 cm. The ACA data clearly reveal the supernova remnant shell ∼ 20--35 arcseconds west of the pulsar, allowing the spectral index between 8.6 and 145 GHz to be determined, In the images above, contours showing the ATCA 3-cm emission at levels of 0.2, 1.0 and 2.0 mJy/beam are overlaid on all the maps for comparison. In the ATCA 3-cm map the half-power beam-width is 0.8 arcsec, and the PWN size is ∼ 8 arcsec × 7 arcsec, so the PWN is fully resolved. With the larger beams in the millimetre maps, the PWN is only partially resolved. The similar structures of the western part of the supernova remnant shell in the ATCA and ACA Band 4 data are apparent. More details are given in the paper to be published in Monthly Notices of the Royal Astronomical Society. |