利用罗曼和鲁宾成像进行罗曼高纬度成像巡天宇宙学的稳健测光
Robust Photometry for Roman High-Latitude Imaging Survey Cosmology Using Roman and Rubin Imaging
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中文总结 AI 辅助
研究针对罗曼高纬度成像巡天宇宙学中测光难题，开发slimfarmer模型拟合测光管道，处理相关噪声等，经模拟图像验证，能恢复星系颜色，校正相关噪声，减轻混合误差，为该领域提供了原型测光管道及关键方法。
中文摘要 AI 辅助
准确精确的测光对于罗曼宇宙学至关重要，它影响测光红移性能、星系和星团选择等。实现稳健测光具有挑战性，因罗曼的深度导致大量源混合。本文开发并验证了slimfarmer，它基于The Farmer，针对罗曼图像中的相关噪声和天文散粒噪声进行处理，调整了模型拟合配置。通过罗曼模拟图像验证，对鲁宾图像模拟进行强制测光。结果表明slimfarmer能恢复星系颜色，正确处理相关噪声对不确定性量化至关重要，联合多目标拟合可减轻混合引起的颜色系统误差。这些结果确立了slimfarmer作为罗曼高纬度成像巡天宇宙学应用的原型测光管道，并确定了稳健测光红移表征所需的相关噪声校正、天文散粒噪声处理和联合多目标拟合。
英文摘要
Accurate and precise photometry is essential for Roman cosmology because it affects photometric-redshift performance, galaxy and cluster selection, tomographic binning, and redshift-distribution characterization. Achieving robust photometry is challenging because Roman's depth leads to substantial source blending, particularly in joint Roman--Rubin analyses, where the two surveys have different spatial resolutions. In this work, we develop and validate slimfarmer, a model-fitting photometry pipeline designed for Roman High-Latitude Imaging Survey (HLIS) cosmological analyses. Building on The Farmer, slimfarmer introduces treatments of the correlated noise present in Roman images and of astronomical shot noise, together with model-fitting configurations tuned for Roman imaging. We validate the pipeline using Roman coadded simulated images and perform forced photometry on matched Rubin image simulations. We find that slimfarmer recovers galaxy colors with the mode of the color residuals within 20 millimag for Roman-based colors and within 70 millimag for Rubin-based colors. Properly accounting for correlated noise is essential for uncertainty quantification, as photometric uncertainties are otherwise underestimated by up to a factor of ~3. We also find that applying multi-object fitting consistently to both Roman and Rubin imaging substantially mitigates blending-induced color systematics. In crowded regions, single-object fitting produces environment-dependent color biases of up to ~0.5 mag, leading to environment-dependent degradation of photometric-redshift performance. Together, these results establish slimfarmer as a prototype photometric pipeline for Roman HLIS cosmology applications and identify the correlated-noise corrections, astronomical shot-noise treatment, and joint Roman--Rubin multi-object fitting required for robust photometric-redshift characterization.
