FROM X-RAY DIPS TO ECLIPSE: WITNESSING DISK REFORMATION IN THE RECURRENT NOVA U Sco
FROM X-RAY DIPS TO ECLIPSE: WITNESSING DISK REFORMATION IN THE RECURRENT NOVA U Sco
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从 X 射线倾斜到日食：见证轮回 NOVA U Sco 中的磁盘改造
DOI：
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发表时间：
2011
期刊：
影响因子：
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通讯作者：
S. Starrfield
中科院分区：
文献类型：
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作者：
J. Ness;B. Schaefer;A. Dobrotka;A. Sa̧dowski;J. Drake;R. Barnard;A. Talavera;R. González;K. Page;M. Hernanz;G. Sala;S. Starrfield
在爆发后的第22.9天和第34.9天，XMM-牛顿在X射线、紫外线和光学上同时观测到了周期性食新星U Sco的第十次爆发。观测到伴星在新星喷出物前的两次完整的通过，以及吸积盘的重新形成。在第22.9天，我们观察到紫外线和光学上的平滑日食，但X射线光曲线的深度下降在第34.9天消失，在所有波段都产生了干净的日食。X射线下降可能是由在沿沿着高度椭圆轨迹移动时与视线相交的吸收物质引起的。来自伴星的冷物质可以解释为什么没有紫外线和可见光的下降。在第34.9天之前X射线下降的消失意味着盘的形成有了重大进展。X射线谱中有光球层的连续发射和强发射线，但没有明显的吸收线。X射线光谱中的连续谱线和发射谱线都表明从第22.9天到第34.9天温度升高。我们在光谱和光变曲线中找到了白色矮星光球辐射的汤普森散射的明显证据。光球层的吸收线在等离子体中的快电子散射过程中会模糊不清。我们还发现了共振线散射的光谱特征，导致观察到的强发射线。它们的优势可能是像Cal 87这样的高倾角系统中的普遍现象。
The tenth recorded outburst of the recurrent eclipsing nova U Sco was observed simultaneously in X-ray, UV, and optical by XMM-Newton on days 22.9 and 34.9 after the outburst. Two full passages of the companion in front of the nova ejecta were observed, as was the reformation of the accretion disk. On day 22.9, we observed smooth eclipses in UV and optical but deep dips in the X-ray light curve that disappeared by day 34.9, yielding clean eclipses in all bands. X-ray dips can be caused by clumpy absorbing material that intersects the line of sight while moving along highly elliptical trajectories. Cold material from the companion could explain the absence of dips in UV and optical light. The disappearance of X-ray dips before day 34.9 implies significant progress in the formation of the disk. The X-ray spectra contain photospheric continuum emission plus strong emission lines, but no clear absorption lines. Both continuum and emission lines in the X-ray spectra indicate a temperature increase from day 22.9 to day 34.9. We find clear evidence in the spectra and light curves for Thompson scattering of the photospheric emission from the white dwarf. Photospheric absorption lines can be smeared out during scattering in a plasma of fast electrons. We also find spectral signatures of resonant line scattering that lead to the observation of the strong emission lines. Their dominance could be a general phenomenon in high-inclination systems such as Cal 87.