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arXiv 2007.15702astro-ph.HE
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新星V959 Mon的X射线演化表明了延迟的喷射和非辐射冲击

X-ray evolution of the nova V959 Mon suggests a delayed ejection and a non-radiative shock

Thomas Nelson, Koji Mukai, Laura Chomiuk, Jennifer L. Sokoloski, Justin D. Linford, Thomas Finzell, Amy J. Mioduszewski, Michael P. Rupen, Jennifer Weston, Raim… 展开作者

Thomas Nelson, Koji Mukai, Laura Chomiuk, Jennifer L. Sokoloski, Justin D. Linford, Thomas Finzell, Amy J. Mioduszewski, Michael P. Rupen, Jennifer Weston, Raimundo Lopes de Oliveira

摘要:

对新星中的冲击气体进行X射线观测,可以为研究喷出物的动力学提供有用的探测手段。在这里,我们报告的X射线观测的新星V959 Mon,这也是在GeV的伽马射线与费米卫星检测。我们发现,X射线光谱与非太阳丰度的双温等离子体模型一致。我们解释的X射线是由于冲击之间的相互作用的慢赤道环面和快速的极地流出,推断从射电观测V959星期一。我们进一步提出,较热的分量,负责大部分的流量,是从反向冲击驱动到快速流出。我们发现在第60天和第140天之间吸收剂的柱密度系统性下降,与对这种情况的预期一致。我们提出了有趣的证据,延迟约40天的喷出物从中央二进制。此外,我们推断出一个相对较小的(几倍10 $^{-6}$ Msun)喷出物质量的冲击,大大低于质量的10 $^4$ K气体从无线电观测推断。最后,我们推断,在我们观测的时候,主要的X射线冲击可能不是辐射性的,而且冲击功率比观测到的X射线亮度高得多。目前还不清楚为什么高X射线亮度,更接近推断的冲击功率,从来没有看到在新星在早期,当冲击预计有足够高的密度是辐射。

英文摘要:

X-ray observations of shocked gas in novae can provide a useful probe of the dynamics of the ejecta. Here we report on X-ray observations of the nova V959 Mon, which was also detected in GeV gamma-rays with the Fermi satellite. We find that the X-ray spectra are consistent with a two-temperature plasma model with non-solar abundances. We interpret the X-rays as due to shock interaction between the slow equatorial torus and the fast polar outflow that were inferred from radio observations of V959 Mon. We further propose that the hotter component, responsible for most of the flux, is from the reverse shock driven into the fast outflow. We find a systematic drop in the column density of the absorber between Days 60 and 140, consistent with the expectations for such a picture. We present intriguing evidence for a delay of around 40 days in the expulsion of the ejecta from the central binary. Moreover, we infer a relatively small (a few times 10$^{-6}$ Msun) ejecta mass ahead of the shock, considerably lower than the mass of 10$^4$ K gas inferred from radio observations. Finally, we infer that the dominant X-ray shock was likely not radiative at the time of our observations, and that the shock power was considerably higher than the observed X-ray luminosity. It is unclear why high X-ray luminosity, closer to the inferred shock power, is never seen in novae at early times, when the shock is expected to have high enough density to be radiative.

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