径向速度实验（RAVE）：第二次数据发布
The Radial Velocity Experiment (RAVE): second data release
摘要：
我们提出了径向速度实验（RAVE）的第二次数据发布，这是一项雄心勃勃的光谱调查，使用英澳天文台（AAO）1.2米英国施密特望远镜上的6dF多目标光谱仪测量多达100万颗恒星的径向速度（RV）和恒星大气参数。它正在获得南半球9<I<12等恒星Ca三重态区域（8，410 - 8，795）的中等分辨率光谱（中值R= 7，500）。在第一次数据发布（Steinmetz et al. 2006）之后，目前发布的RV样本增加了一倍，现在包含了2003年4月11日至2005年3月31日期间在141个夜晚观察到的49，327颗恒星的51，829个RV。与外部数据集的比较表明，自2004年4月3日以来收集的新数据显示标准差为1.3公里/秒，比第一次发布的数据好两倍。该数据首次包含来自21，121颗恒星的22，407个光谱的恒星参数值。它们是通过惩罚χ^2方法推导出来的，该方法使用了从最新版本的库鲁茨模型中计算出的合成光谱的广泛网格。从与外部数据集的比较，我们的保守估计的恒星参数的误差（S/N=40的光谱）是400 K的温度，0.5 dex的重力，和0.2 dex的金属丰度。然而，我们注意到，从822颗恒星的重复RAVE观测估计的内部误差至少小了2倍。我们证明，结果显示没有系统的偏移，如果来自光度或补充光谱分析的值相比。数据发布包括自行和光度测量。它可以通过RAVE网页访问：http://www.rave-survey.org和通过CDS。
英文摘要：
We present the second data release of the Radial Velocity Experiment (RAVE), an ambitious spectroscopic survey to measure radial velocities (RVs) and stellar atmosphere parameters of up to one million stars using the 6dF multi-object spectrograph on the 1.2-m UK Schmidt Telescope of the Anglo-Australian Observatory (AAO). It is obtaining medium resolution spectra (median R=7,500) in the Ca-triplet region (8,410--8,795 Å) for southern hemisphere stars in the magnitude range 9<I<12. Following the first data release (Steinmetz et al. 2006) the current release doubles the sample of published RVs, now containing 51,829 RVs for 49,327 individual stars observed on 141 nights between April 11 2003 and March 31 2005. Comparison with external data sets shows that the new data collected since April 3 2004 show a standard deviation of 1.3 km/s, about twice better than for the first data release. For the first time this data release contains values of stellar parameters from 22,407 spectra of 21,121 individual stars. They were derived by a penalized χ^2 method using an extensive grid of synthetic spectra calculated from the latest version of Kurucz models. From comparison with external data sets, our conservative estimates of errors of the stellar parameters (for a spectrum with S/N=40) are 400 K in temperature, 0.5 dex in gravity, and 0.2 dex in metallicity. We note however that the internal errors estimated from repeat RAVE observations of 822 stars are at least a factor 2 smaller. We demonstrate that the results show no systematic offsets if compared to values derived from photometry or complementary spectroscopic analyses. The data release includes proper motion and photometric measurements. It can be accessed via the RAVE webpage: http://www.rave-survey.org and through CDS.
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