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arXiv 0904.2210astro-ph.COastro-ph.HE
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用GRB探测高z宇宙

GRB Probes of the High-z Universe with EXIST

Jonathan Grindlay, the EXIST Team

摘要:

高能X射线成像巡天望远镜(EXIST)的任务概念是优化的高Z伽玛暴作为早期宇宙的探测器的研究。高能望远镜(HET)采用4.5m^2 5- 600 keV(CZT; 0.6mm像素)探测器平面,用于编码孔径成像,视场为90度x 70度(>10%编码分数),分辨率为2',<20”(90% conf.)对于>5 sigma源的位置,EXIST将执行快速(<200秒)转换到GRB。用0.1 - 10 keV的软X射线望远镜和1.1米的光学红外望远镜同时获得了0.3 - 0.52微米、0.52 - 0.9微米、0.9 - 1.38微米和1.38 - 2.3微米四个波段的瞬发图像和光谱。初始图像(100 s)将在HET误差圆内从<2”提示SXI位置或从VIS与IR丢失或变化中产生提示识别。然后,一个自主航天器重新定位(<30”)将把伽马射线暴放在0.3”x 4”的狭缝上,在0.3 - 0.9微米和0.9 - 2.3微米波段上获得R = 3000(AB <21)或R =30(AB ~21-25)的瞬发光谱。这将为大多数伽玛暴提供约500- 2000秒的红移,如果存在这样的伽玛暴,则达到z ~20(莱曼-α破裂),并为研究宿主星系和局部再电离斑块以及干预宇宙结构提供光谱。EXIST预计每年约有600个伽玛暴,其中z >7的伽玛暴约占7-10%,它将开启早期宇宙研究的新纪元,并开展活动星系核和瞬变源科学的丰富计划。概述了伽玛射线暴的科学目标,并简要讨论了整个任务的设计和操作,并举例说明高z伽玛射线暴IRT光谱。EXIST被提议作为一项为期5年的中型任务,最早可能在2017年发射。

英文摘要:

The Energetic X-ray Imaging Survey Telescope (EXIST) mission concept is optimized for study of high-z GRBs as probes of the early Universe. With a High Energy Telescope (HET) incorporating a 4.5m^2 5-600keV (CZT; 0.6mm pixels) detector plane for coded aperture imaging a 90deg x 70deg (>10% coding fraction) field of view with 2' resolution and <20" (90% conf.) positions for >5 sigma sources, EXIST will perform rapid (<200sec) slews onto GRBs. Prompt images and spectra are obtained with a co-aligned soft X-ray telescope (SXI; 0.1 - 10keV) and with a 1.1m optical-IR telescope (IRT) simultaneously in 4 bands (0.3 - 0.52micron, 0.52 - 0.9micron, 0.9 - 1.38micron, and 1.38 - 2.3micron). An initial image (100s) will yield prompt identification within the HET error circle from a <2" prompt SXI position; or from VIS vs. IR dropouts or variability. An autonomous spacecraft re-point (<30") will then put the GRB on a 0.3" x 4" slit for either R = 3000 (for AB <21) or R =30 (for AB ~21-25) prompt spectra over the 0.3 - 0.9 micron and 0.9 - 2.3 micron bands. This will provide onboard redshifts within ~500-2000sec for most GRBs, reaching z ~20 (for Lyman-alpha breaks) if such GRBs exist, and spectra for studies of the host galaxy and local re-ionization patchiness as well as intervening cosmic structure. With ~600 GRBs/yr expected, including ~7-10% expected at z >7, EXIST will open a new era in studies of the early Universe as well as carry out a rich program of AGN and transient-source science. An overview of the GRB science objectives and a brief discussion of the overall mission design and operations is given, and example high-z GRB IRT spectra are shown. EXIST is being proposed to the Astro2010 Decadal Survey as a 5 year Medium Class mission that could be launched as early as 2017.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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