发表机构
Shanghai Jiao Tong University; Peking University（上海交通大学; 北京大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究利用模拟图像与HST/JWST观测评估EGS场暗弱星系的探测完备性和结构测量可靠性，提出经验判据区分真实与虚假探测，生成包含59,646个天体的暗弱星系星表。
AI 中文摘要
可靠的暗弱极限星表对于星系演化的统计研究至关重要。然而，暗弱星系的探测和结构测量仍然具有挑战性。我们利用HST和JWST的模拟图像与观测数据，评估了CANDELS/EGS场中暗弱星系的探测完备性和结构参数不确定性。该框架同样适用于大型高红移巡天项目，包括Euclid、即将开展的CSST以及Nancy Grace Roman太空望远镜。我们使用1.5σ阈值在EGS F160W马赛克图像中探测源，并通过逼真的模拟图像量化探测完备性和虚假探测率。模拟星系对测试评估了混叠效应对源探测以及sersic拟合中结构测量的影响。此外，与CEERS观测的重叠区域被用于推导一个经验判据，以利用HST测光数据区分真实的暗弱星系与虚假探测。我们在CANDELS/EGS场中识别出72,467个源，其中57,444个在F160W波段暗于25星等。对于亮于25星等的天体，探测完备性超过95%，但在27星等以上降至<50%（虚假探测率>50%）。单一sersic模型得出的结构参数在mH=25星等以下保持可靠。对于25<mH<27星等的星系，sersic指数的系统偏差达到Δn≈5-70%，而Δq从约-0.03降至-0.27。近距离伴星（约0.3角秒）会在恢复的sersic星等和形态中引入可测量的偏差，而在较大间距时影响可忽略不计。基于mH、F814W-F160W颜色、R50和zphot的经验判据能够将真实暗弱星系与虚假探测区分开来，达到72%的完备性和84%的纯净度。该判据最终生成包含59,646个天体的星表，与先前CANDELS在亮星等端的测量结果一致，同时延伸至更暗的极限。
英文摘要
Reliable catalogs at the faint limit are essential for statistical studies of galaxy evolution. However, detection and structural measurements of faint galaxies remain challenging. We evaluate detection completeness and structural parameter uncertainties of faint galaxies in the CANDELS/EGS field using mock images and observations from the HST and JWST. The framework is also applicable to large high-redshift surveys, including Euclid, the upcoming CSST, and the Nancy Grace Roman Space Telescope. We detect sources in the EGS F160W mosaic using a 1.5σthreshold and quantify detection completeness and false-detection rates with realistic mock images. Mock galaxy-pair tests assess blending effects on both source detection and structural measurements in sersic fitting. In addition, the overlap with CEERS observations is used to derive an empirical criterion for separating true faint galaxies from fake detections using HST photometry. We identify 72,467 sources in the CANDELS/EGS field, including 57,444 fainter than 25 mag in F160W. Detection completeness exceeds 95% for objects brighter than 25 mag but declines to <50% beyond 27 mag (with false detection rate>50%). Structure parameters from single sersic modeling are reliable down to mH = 25 mag. For galaxies at 25<mH<27 mag, systematic biases in the sersic index reach Δn \approx 5-70%, while Δq decreases from approximately -0.03 to -0.27. Close companions (~0.3 arcsec) introduce measurable biases in recovered sersic magnitudes and shapes, while the impact becomes negligible at larger separations. An empirical criterion based on mH, F814W-F160W color, R50, and zphot separates true faint galaxies from false detections, reaching 72% completeness and 84% purity. It yields a final catalog of 59,646 objects consistent with previous CANDELS measurements at bright magnitudes while reaching fainter limits.
CommentsAccepted for publication in A&A
