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arXiv 1003.4313astro-ph.SR
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木曾巡天中白矮星的光谱分析

A Spectroscopic Analysis of White Dwarfs in the Kiso Survey

M. -M. Limoges, P. Bergeron

摘要:

本文对木曾巡天中发现的白矮星进行了光谱分析。在Kiso Schmidt紫外线过量巡天(KUV星)中获得了所有DA星和DB星的高信噪比光谱观测。这些观测导致了几个KUV天体的重新分类,包括发现了三个未解决的DA+DB双简并双星。大气参数(Teff和log g)从详细的模型大气拟合光学光谱数据。我们的样品的质量分布的特点是由一个平均值为0.606 Msun和0.135 Msun的分散度的DA星,和0.758 Msun和0.192 Msun的分散度的DB星。从我们的光谱拟合获得的绝对视觉星等使我们能够推导出一个改进的光度函数的DA和DB星确定的木曾调查。我们的光度函数被发现是显着不同的早期估计的基础上经验光度校准MV相同的样品。DA星的结果现在看起来与使用相同光谱方法的PG巡天所获得的结果完全一致。在木曾巡天中,Mv<12.75的DA星的空间密度为2.80 × 10 ^-4 pc^-3,比PG巡天中的值小9.6%。这两个调查的完整性进行了简要讨论。

英文摘要:

We present a spectroscopic analysis of white dwarfs found in the Kiso survey. Spectroscopic observations at high signal-to-noise ratio have been obtained for all DA and DB stars in the Kiso Schmidt ultraviolet excess survey (KUV stars). These observations led to the reclassification of several KUV objects, including the discovery of three unresolved DA+DB double degenerate binaries. The atmospheric parameters (Teff and log g) are obtained from detailed model atmosphere fits to optical spectroscopic data. The mass distribution of our sample is characterized by a mean value of 0.606 Msun and a dispersion of 0.135 Msun for DA stars, and 0.758 Msun and a dispersion of 0.192 Msun for DB stars. Absolute visual magnitudes obtained from our spectroscopic fits allow us to derive an improved luminosity function for the DA and DB stars identified in the Kiso survey. Our luminosity function is found to be significantly different from earlier estimates based on empirical photometric calibrations of Mv for the same sample. The results for the DA stars now appear entirely consistent with those obtained for the PG survey using the same spectroscopic approach. The space density for DA stars with Mv<12.75 is 2.80X10^-4 pc^-3 in the Kiso survey, which is 9.6% smaller than the value found in the PG survey. The completeness of both surveys is briefly discussed.

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