Radio observations of supernova remnant G1.9+0.3
Radio observations of supernova remnant G1.9+0.3
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DOI：
10.1093/mnras/stz3439
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发表时间：
2019-12
影响因子：
4.8
通讯作者：
K. Luken;M. Filipovi'c;N. Maxted;R. Kothes;R. Norris;J. Allison;R. Blackwell;C. Braiding;R. Brose;M. Burton;A. D. De Horta-A.-D.-De Horta-2126674326;T. Galvin;L. Harvey-Smith;N. Hurley-Walker;D. Leahy;N. Ralph;Q. Roper;G. Rowell;I. Sushch;D. Urošević;G. Wong
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文献类型：
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作者：
K. Luken;M. Filipovi'c;N. Maxted;R. Kothes;R. Norris;J. Allison;R. Blackwell;C. Braiding;R. Brose;M. Burton;A. D. De Horta-A.-D.-De Horta-2126674326;T. Galvin;L. Harvey-Smith;N. Hurley-Walker;D. Leahy;N. Ralph;Q. Roper;G. Rowell;I. Sushch;D. Urošević;G. Wong
我们提出了1-10 GHz的无线电连续通量密度，光谱指数，偏振和旋转措施（RM）的最年轻的已知银河系超新星遗迹（SNR）G1.9+0.3，从澳大利亚望远镜紧凑阵列的观测图像。我们在1984年至2017年期间进行了一项跨越八个时代的扩张研究，得出的结果与之前的G1.9+0.3扩张研究一致。我们发现一个平均射电连续谱扩展速率为（0.78 ± 0.09）% yr−1（或在假设距离为8.5 kpc时为1.8900 km s−1），尽管扩展速率在SNR范围内变化。在2016年至2017年的最近一个时期，我们观察到北方地区的扩张速度快于预期。我们发现G1.9+0.3的全局谱指数为−0.81 ± 0.02（76 MHz-10 GHz）。然而，朝向北方地区，观测到的无线电频谱明显变陡（λ-1）。对于G1.9+0.3的两个所谓（东和西）“耳朵”，我们发现RM值非常不同，分别为400-600和100-200 rad m2。射电连续辐射的部分偏振达到（19 ± 2）%，与其他稍老的SNR（如Cas A）一致。
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 ∼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 (∼−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 m2, respectively. The fractional polarization of the radio continuum emission reaches (19 ± 2) per cent, consistent with other, slightly older, SNRs such as Cas A.