期刊
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
卷 492, 期 2, 页码 2606-2621出版社
OXFORD UNIV PRESS
DOI: 10.1093/mnras/stz3439
关键词
supernovae: general; ISM: individual objects: G1.9+0.3; ISM: supernova remnants; radio continuum: ISM
资金
- Commonwealth of Australia
- Ministry of Education, Science, and Technological Development of the Republic of Serbia [176005]
We present 1-10 GHz radio continuum flux density, spectral index, polarization, and rotation measure (RM) images of the youngest known Galactic supernova remnant (SNR) G1.9+0.3, using observations from the Australia Telescope Compact Array. We have conducted an expansion study spanning eight epochs between 1984 and 2017, yielding results consistent with previous expansion studies of G1.9+0.3. We find a mean radio continuum expansion rate of (0.78 +/- 0.09) per cent yr(-1) (or similar to 8900 km s(-1) at an assumed distance of 8.5 kpc), although the expansion rate varies across the SNR perimetre. In the case of the most recent epoch between 2016 and 2017, we observe faster-than-expected expansion of the northern region. We find a global spectral index for G1.9+0.3 of -0.81 +/- 0.02 (76 MHz-10 GHz). Towards the northern region, however, the radio spectrum is observed to steepen significantly (similar to-1). Towards the two so-called (east and west) 'ears' of G1.9+0.3, we find very different RM values of 400-600 and 100-200 rad m(2), respectively. The fractional polarization of the radio continuum emission reaches (19 +/- 2) per cent, consistent with other, slightly older, SNRs such as Cas A.
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