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arXiv 0904.3170astro-ph.GA
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低表面亮度SNR G65的射电性质.2+5.7

Radio properties of the low surface brightness SNR G65.2+5.7

L. Xiao, W. Reich, E. Fürst, J. L. Han

摘要:

这种信噪比的许多物理特性,如频谱和极化,只能通过无线电观测来研究。分别用Effelsberg 100 m和乌鲁木齐25 m望远镜对$λ$ 11 cm和$λ$ 6 cm连续谱和偏振谱进行了观测,信噪比为G65.2+5.7,研究了积分谱、谱指数分布和磁场特性。还使用了来自Effelsberg 100米望远镜的$λ$ 21厘米档案数据。G65.2+5.7在$λ11$ cm和$λ6$ cm处的积分通量密度分别为$21.9\pm3.1$ Jy和16.8 $\pm$ 1.8 Jy。从83 MHz到4.8 GHz的幂律谱($S\simν^α$)与$α= -0.58\pm0.07$拟合良好。空间光谱变化很小。沿北壳层在两个波长处都观察到强去极化。SNR G65.2+5.7的南半球壳层在$λ6$ cm处的偏振度高达54%。在$λ11$ cm处有明显的去极化现象,并与弥漫极化的银河辐射相混淆。利用均分原理,我们估计了南大陆壳的磁场强度约为20 $μ$ G(填充因子1)~ 50 $μ$ G(填充因子0.1)。微弱的HI壳可能与SNR相关联。尽管它的X射线和光学发射异常强烈,表面亮度非常低,但SNR G65.2+5.7的射电性质被认为是典型的演化壳型SNR。SNR G65.2+5.7可能在预吹腔中膨胀,如HI气体不足和可能的HI壳所示。

英文摘要:

Many physical properties of this SNR such as spectrum and polarization can only be investigated by radio observations. The $λ$11 cm and $λ$6\ cm continuum and polarization observations of SNR G65.2+5.7 were made with the Effelsberg 100-m and the Urumqi 25-m telescopes, respectively, to investigate the integrated spectrum, the spectral index distribution, and the magnetic field properties. $λ$21 cm archival data from the Effelsberg 100-m telescope have been also used. The integrated flux densities of G65.2+5.7 at $λ11$ cm and $λ6$ cm are $21.9\pm3.1$ Jy and 16.8$\pm$1.8 Jy, respectively. The power-law spectrum ($S\simν^α$) is well fitted by $α= -0.58\pm0.07$ from 83 MHz to 4.8 GHz. Spatial spectral variations are small. Along the northern shell strong depolarizion is observed at both wavelengths. The southern filamentary shell of SNR G65.2+5.7 is polarized up to 54% at $λ6$ cm. There is significant depolarization at $λ11$ cm and confusion with diffuse polarized Galactic emission. Using equipartition principle, we estimated the magnetic field strength for the southern filamentary shell about 20 $μ$G (filling factor 1) to 50 $μ$G (filling factor 0.1). A faint HI shell may be associated with the SNR. Despite its unusual strong X-ray and optical emission and its very low surface brightness, the radio properties of SNR G65.2+5.7 are found to be typical for evolved shell type SNRs. SNR G65.2+5.7 may be expanding in a preblown cavity as indicated by a deficit of HI gas and a possible HI-shell.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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