论文标题
浓缩咖啡高分辨率4x2套筒的性能，以表征介入淡淡的类星体的中间吸收器
Performance of ESPRESSO's high resolution 4x2 binning for characterizing intervening absorbers towards faint quasars
论文作者
论文摘要
截至2021年10月（周期108），欧洲南部天文台（ESO）提供了一种新的意式浓缩仪模式模式，旨在将高分辨率光栅与4x2套筒（按光谱进行空间； HR42模式），其特定目标是通过Paranal的单个单位望远镜观察微弱的目标。我们使用了四个小时的Quasar J0003-2603的目标观测来验证了新的HR42模式，该观察已知可以在视线沿线托管中间的金属贫困吸收器。通过与具有相似集成时间但较低分辨率的同一目标的uves频谱进行比较，评估了浓缩咖啡HR42模式（解决功率R〜137 000）的功能（R〜48 000）。对于两个数据集，我们测试了使用VOIGT配置拟合分解中间吸收器的速度曲线的能力，并提取了CIV，Ni，Siii，Alii，Feii和Niii的总柱密度。在〜3倍分辨能力和〜2倍的S/N中，在几乎同等的暴露时间中，浓缩咖啡数据能够准确地表征吸收线的各个组件与比较UVE的数据，但具有识别Uves未检测到的狭窄组件的额外奖励。为了使尺寸提供类似的光谱分辨率（r> 100 000； 0.3'缝）和浓缩咖啡的广泛波长覆盖范围，ESO提供的曝光时间计算器（ETC）估计在两个设置上的暴露时间分布8小时；需要花费两倍的时间投资，而不是浓缩咖啡的HR42模式的时间投资，同时无法正确采样尺寸的光谱分辨率元素。因此，意式浓缩咖啡的HR42模式几乎具有三倍的UVE（0.8''缝隙以匹配Paranal处的典型环境条件），并为等效暴露时间提供了类星体吸收特征的更准确表征。
As of October 2021 (Period 108), the European Southern Observatory (ESO) offers a new mode of the ESPRESSO spectrograph designed to use the High Resolution grating with 4x2 binning (spatial by spectral; HR42 mode) with the specific objective of observing faint targets with a single Unit Telescope at Paranal. We validated the new HR42 mode using four hours of on-target observations of the quasar J0003-2603, known to host an intervening metal-poor absorber along the line of sight. The capabilities of the ESPRESSO HR42 mode (resolving power R~137 000) were evaluated by comparing to a UVES spectrum of the same target with a similar integration time but lower resolving power (R~48 000). For both data sets we tested the ability to decompose the velocity profile of the intervening absorber using Voigt profile fitting and extracted the total column densities of CIV, NI, SiII, AlII, FeII, and NiII. With ~3x the resolving power and ~2x lower S/N for a nearly equivalent exposure time, the ESPRESSO data is able to just as accurately characterize the individual components of the absorption lines as the comparison UVES data, but has the added bonus of identifying narrower components not detected by UVES. For UVES to provide similar spectral resolution (R>100 000; 0.3'' slit) and the broad wavelength coverage of ESPRESSO, the Exposure Time Calculator (ETC) supplied by ESO estimates 8 hrs of exposure time spread over two settings; requiring double the time investment than that of ESPRESSO's HR42 mode whilst not properly sampling the UVES spectral resolution element. Thus ESPRESSO's HR42 mode offers nearly triple the resolving power of UVES (0.8'' slit to match typical ambient conditions at Paranal) and provides more accurate characterization of quasar absorption features for an equivalent exposure time.
