The Large Array Survey Telescope—Pipeline. I. Basic Image Reduction and Visit Coaddition

IF 3.3 3区 物理与天体物理 Q2 ASTRONOMY & ASTROPHYSICS
E. O. Ofek, Y. Shvartzvald, A. Sharon, C. Tishler, D. Elhanati, N. Segev, S. Ben-Ami, G. Nir, E. Segre, Y. Sofer-Rimalt, A. Blumenzweig, N. L. Strotjohann, D. Polishook, A. Krassilchtchikov, A. Zenin, V. Fallah Ramazani, S. Weimann, S. Garrappa, Y. Shanni, P. Chen, E. Zimmerman
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Abstract

The Large Array Survey Telescope (LAST) is a wide-field telescope designed to explore the variable and transient sky with a high cadence and to be a test-bed for cost-effective telescope design. A LAST node is composed of 48 (32 already deployed), 28 cm f/2.2 telescopes. A single telescope has a 7.4 deg2 field of view and reaches a 5σ limiting magnitude of 19.6 (21.0) in 20 (20 × 20) s (filter-less), while the entire system provides a 355 deg2 field of view. The basic strategy of LAST is to obtain multiple 20 s consecutive exposures of each field (a visit). Each telescope carries a 61 Mpix camera, and the system produces, on average, about 2.2 Gbit s−1. This high data rate is analyzed in near real-time at the observatory site, using limited computing resources (about 700 cores). Given this high data rate, we have developed a new, efficient data reduction and analysis pipeline. The LAST data pipeline includes two major parts: (i) Processing and calibration of single images, followed by a coaddition of the visit’s exposures. (ii) Building the reference images and performing image subtraction and transient detection. Here we describe in detail the first part of the pipeline. Among the products of this pipeline are photometrically and astrometrically calibrated single and coadded images, 32 bit mask images marking a wide variety of problems and states of each pixel, source catalogs built from individual and coadded images, Point-Spread Function photometry, merged source catalogs, proper motion and variability indicators, minor planets detection, calibrated light curves, and matching with external catalogs. The entire pipeline code is made public. Finally, we demonstrate the pipeline performance on real data taken by LAST.
大型阵列巡天望远镜管道。I. 基本图像缩减和访问叠加
大型阵列巡天望远镜(LAST)是一台宽视场望远镜,旨在高频率地探索变星和瞬变天空,并作为成本效益望远镜设计的试验平台。LAST 节点由 48 台(32 台已部署)28 厘米 f/2.2 望远镜组成。单台望远镜的视场为 7.4 平方分米,在 20 (20 × 20) 秒(无滤波器)内达到 19.6 (21.0) 的 5σ 极限星等,而整个系统的视场为 355 平方分米。LAST 的基本策略是对每个视场进行多次 20 秒的连续曝光(访问)。每台望远镜携带一台 6100 万像素的相机,系统平均产生约 2.2 Gbit s-1。观测站利用有限的计算资源(约 700 个内核)对这一高数据率进行近乎实时的分析。鉴于如此高的数据传输率,我们开发了一种新的、高效的数据还原和分析管道。LAST 数据管道包括两个主要部分:(i) 处理和校准单幅图像,然后对访问的曝光进行共同加法。(ii) 建立参考图像并进行图像减法和瞬态检测。在此,我们将详细介绍该流程的第一部分。该流水线的产品包括:经过光度和天体测量校准的单幅图像和共加图像、标记了各种问题和每个像素状态的 32 位掩膜图像、根据单幅图像和共加图像建立的源星表、点散布函数光度测量、合并源星表、适当运动和变率指标、小行星探测、校准光曲线,以及与外部星表的匹配。整个管道代码都是公开的。最后,我们在 LAST 拍摄的真实数据上演示了该管道的性能。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
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来源期刊
Publications of the Astronomical Society of the Pacific
Publications of the Astronomical Society of the Pacific 地学天文-天文与天体物理
CiteScore
6.70
自引率
5.70%
发文量
103
审稿时长
4-8 weeks
期刊介绍: The Publications of the Astronomical Society of the Pacific (PASP), the technical journal of the Astronomical Society of the Pacific (ASP), has been published regularly since 1889, and is an integral part of the ASP''s mission to advance the science of astronomy and disseminate astronomical information. The journal provides an outlet for astronomical results of a scientific nature and serves to keep readers in touch with current astronomical research. It contains refereed research and instrumentation articles, invited and contributed reviews, tutorials, and dissertation summaries.
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