The SDSS-V local volume mapper telescope system
The SDSS-V local volume mapper telescope system
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SDSS-V 局部体积映射望远镜系统
DOI：
10.1117/12.2561419
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Gaessler, Wolfgang
中科院分区：
文献类型：
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作者：
Herbst, Tom M.;Bilgi, Pavaman;Bizenberger, Peter;Blanc, Guillermo;Briegel, Florian;Case, Scott;Drory, Niv;Feger, Tobias;Froning, Cynthia S.;Gaessler, Wolfgang
斯隆数字巡天五号（SDSS-V）是一个全天空的光谱巡天，对600万个以下的天体进行巡天，旨在解码银河系的历史，揭示恒星的内部运作，调查太阳系的起源，并跟踪宇宙中超大质量黑洞的生长。本地体积映射器（LVM）是组成SDSS-V的三个调查之一。LVM将采用一个由四个望远镜组成的协调系统，为智利拉斯坎帕纳斯天文台的三个光纤光谱仪提供数据。目标是在360-980 nm波长范围内绘制大约2500平方度的银河平面图，光谱分辨率为R~4000。这些观测将首次揭示银河系内不同的气体环境如何相互作用以及与恒星群相互作用，从而产生我们观察到的大规模星际介质。以这种空间分辨率精确测绘和校准天空的大部分区域需要一种独特的望远镜系统。这四台望远镜的直径都是16厘米，这使得它们比它们所使用的仪器要小得多，也轻得多。一个望远镜将承载科学IFU，其中包含约1800根排列成密集六边形的光纤。另外两个校准望远镜将观察科学IFU附近的场，以校准地球气辉和其他地冠发射。第四，分光光度望远镜将对明亮的恒星进行快速观测（通常在单次IFU /校准曝光期间为12颗），以校正大地吸收线和整体消光。来自所有三种望远镜的光纤将散布在光谱仪的入口狭缝中，允许同时进行科学和校准曝光。虽然比下一代的巨型望远镜小得多，但LVM望远镜也必须接近物理光学的极限，而且LVM调查的几何形状和范围提出了独特的挑战。例如，在拉斯坎帕纳斯的这种望远镜，光学像差、衍射、视宁度和（未校正的）大气色散的影响都是相当的。这一点，再加上多年来需要重复和可靠的测量，导致了一些非常规的设计选择。本文介绍了LVM望远镜系统的初步设计，并讨论了导致基线选择的要求和权衡。
The Sloan Digital Sky Survey V (SDSS-V) is an all-sky spectroscopic survey of <6 million objects, designed to decode the history of the Milky Way, reveal the inner workings of stars, investigate the origin of solar systems, and track the growth of supermassive black holes across the Universe. The Local Volume Mapper (LVM) is one of three surveys that form SDSS-V. LVM will employ a coordinated system of four telescopes feeding three fiber spectrographs at Las Campanas Observatory in Chile. The goal is to map approximately 2500 square degrees of the Galactic plane over the wavelength range 360-980 nm with R~4000 spectral resolution. These observations will reveal for the first time how distinct gaseous environments within the Galaxy interact with each other and with the stellar population, producing the large-scale interstellar medium that we observe. Accurately mapping and calibrating a substantial portion of the sky at this spatial resolution requires a unique type of telescope system. Each of the four LVM telescopes has a diameter of 16 cm, making them considerably smaller and lighter than the instruments they feed. One telescope will host the science IFU containing ~1800 fibers arranged in a close-packed hexagon. Two additional Calibration telescopes will observe fields adjacent to the science IFU, in order to calibrate out terrestrial airglow and other geo-coronal emission. The fourth, Spectrophotometric telescope will make rapid observations of bright stars (typically 12 during a single IFU / Calibration exposure) to correct for telluric absorption lines and overall extinction. The fibers from all three types of telescope will be interspersed in the entrance slits of the spectrographs, allowing for simultaneous science and calibration exposures. Although considerably smaller than the next generation of giants, the LVM telescopes must also operate close to the limits of physical optics, and the geometry and scope of the LVM survey present unique challenges. For example, with this type of telescope at the Las Campanas site, the effects of optical aberrations, diffraction, seeing, and (uncorrected) atmospheric dispersion are all of comparable scale. This, coupled with the need for repeated and reliable measurements over years, leads to some unconventional design choices. This paper presents the preliminary design of the LVM telescope system and discusses the requirements and tradeoffs that led to the baseline choices.