论文标题
中国空间站望远镜（CSST）恒星径向速度的精度
Precision of The Chinese Space Station Telescope (CSST) Stellar Radial Velocities
论文作者
论文摘要
中国空间站望远镜（CSST）光谱调查计划计划提供高质量的低分辨率（$ r> 200 $）的无限光谱，以数亿个目标，降低到约21个MAG的限制幅度，涵盖了大型调查区域（1750000 $^2 $）和宽阔的波长范围（255-1000 nm by 3 by 3 Bands by 3 brands by 3 by 3 by 3 by g g v gu，gv）。在这项工作中，我们使用下一代光谱库的经验光谱以$ r = 250 $模拟CSST恒星光谱，并研究它们在测量径向速度方面的能力。我们发现，速度不确定性在很大程度上取决于有效温度，仅对于FGK星而言，金属性弱，几乎不在表面重力上。可以将恒星径向速度的精确度传递至$ 3 \，\ Mathrm {km} \，\ Mathrm {s}^{ - 1} $的afgkm Stars，而大约$ 10 \，\ 10 \，\，\ Mathrm {Km}还探索了使用单GU/GV/GI带光谱的100。速度不确定性的（SNR）。鉴于相同的SNR，GU乐队表现最好，GV乐队排名第二，然后是GI乐队。研究了光谱归一化和不完善模板对速度测量值的影响，发现非常弱。考虑并发现由波长校准引起的不确定性是中等的。鉴于径向速度的可能精度，CSST光谱调查可以实现有趣的科学，例如搜索高速恒星。还讨论了我们的结果的局限性。
The Chinese Space Station Telescope (CSST) spectroscopic survey plans to deliver high-quality low-resolution ($R > 200$) slitless spectra for hundreds of millions of targets down to a limiting magnitude of about 21 mag, covering a large survey area (17500 deg$^2$) and a wide wavelength range (255-1000 nm by 3 bands GU, GV, and GI). In this work, we use empirical spectra of the Next Generation Spectral Library to simulate the CSST stellar spectra at $R = 250$, and investigate their capabilities in measuring radial velocities. We find that velocity uncertainties depend strongly on effective temperature, weakly on metallicity for only FGK stars, and hardly on surface gravity. It is possible to deliver stellar radial velocities to a precision of about $3 \,\mathrm{km}\,\mathrm{s}^{-1}$ for AFGKM stars, and about $10 \,\mathrm{km}\,\mathrm{s}^{-1}$ for OB stars, at signal-to-noise ratio (SNR) of 100. Velocity uncertainties using single GU/GV/GI band spectra are also explored. Given the same SNR, the GU band performs best, the GV band the second best, and then the GI band. The effects of spectral normalization and imperfect template on velocity measurements are investigated and found to be very weak. The uncertainties caused by wavelength calibration are considered and found to be moderate. Given the possible precision of radial velocities, the CSST spectroscopic survey can enable interesting science such as searching for hyper-velocity stars. Limitations of our results are also discussed.
