arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1901.03485astro-ph.IMastro-ph.GA
收藏

基于图像模拟的中国空间站光学巡天(CSS-OS)有效星系计数分析

The analysis of effective galaxies number count for Chinese Space Station Optical Survey(CSS-OS) by image simulation

Xin Zhang, Li Cao, Xianmin Meng

AI总结:

本文通过图像模拟评估中国空间站光学巡天CSS-OS的星系探测能力,发现其大面积巡天和深度巡天的有效星系计数分别约为13和40 arcmin^-2,并在小星系高分辨率探测方面优于LSST。

摘要:

中国空间站光学巡天(CSS-OS)是一项探索浩瀚宇宙的任务。该任务将配备一台2米空间望远镜,开展多波段近紫外-光学大面积巡天(覆盖超过40%的天空)和深度巡天(约1%的天空),以服务于宇宙学和天文学科学目标。星系探测是实现科学目标的最重要方法之一。本文通过图像模拟方法,评估了CSS-OS在i波段(大面积巡天深度i约26等,深度巡天约27等,点源,5σ)的星系面密度。我们还将CSS-OS探测到的星系与LSST(i约27等,点源,5σ)进行了比较。在我们的模拟中,使用HUDF星系星表来生成模拟图像,因为其积分时间足够长,能够满足CSS-OS和LSST星系分析的完备性要求。星系表面轮廓和光谱由星表中的形态信息、测光红移和SED生成。同时考虑了仪器特性和环境条件来生成模拟星系图像。CSS-OS和LSST的星系均通过SExtractor从模拟i波段图像中提取,并与原始星表进行匹配。通过对提取星系的分析,我们发现CSS-OS大面积巡天、CSS-OS深度巡天和LSST的有效星系计数分别约为13 arcmin^-2、40 arcmin^-2和42 arcmin^-2。此外,CSS-OS在具有高空间分辨率的小星系探测方面展现出优势,尤其是在深度巡天中:CSS-OS深度巡天探测到的星系中约有20%未被LSST探测到,这些星系的有效半径较小,re < 0.3"。

英文摘要:

The Chinese Space Station Optical Survey (CSS-OS) is a mission to explore the vast universe. This mission will equip a 2-meter space telescope to perform a multi-band NUV-optical large area survey (over 40% of the sky) and deep survey (~1% of the sky) for the cosmological and astronomical goals. Galaxy detection is one of the most important methods to achieve scientific goals. In this paper, we evaluate the galaxy number density for CSS-OS in i band (depth, i ~26 for large area survey and ~27 for the deep survey, point source, 5-sigma by the method of image simulation. We also compare galaxies detected by CSS-OS with that of LSST (i~27, point source, 5-sigma. In our simulation, the HUDF galaxy catalogs are used to create mock images due to long enough integration time which meets the completeness requirements of the galaxy analysis for CSS-OS and LSST. The galaxy surface profile and spectrum are produced by the morphological information, photometric redshift and SEDs from the catalogs. The instrumental features and the environmental condition are also considered to produce the mock galaxy images. The galaxies of CSS-OS and LSST are both extracted by SExtractor from the mock i band image and matched with the original catalog. Through the analysis of the extracted galaxies, we find that the effective galaxy number count is ~13 arcmin^-2, ~40 arcmin^-2 and ~42 arcmin^-2 for CSS-OS large area survey, CSS-OS deep survey and LSST, respectively. Moreover, CSS-OS shows the advantage in small galaxy detection with high spatial resolution, especially for the deep survey: about 20% of the galaxies detected by CSS-OS deep survey are not detected by LSST, and they have a small effective radius of re < 0.3".

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。

↑