暗能量光谱仪数据发布1（DR1）亮星系巡天中670万个星系的物理性质：光谱拟合与模拟光谱的系统测试
Physical Properties of 6.7 Million Galaxies from the DESI Bright Galaxy Survey: Spectral Fitting and Systematic Tests with Mock Spectra
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中文总结 AI 辅助
该研究基于约670万个星系光谱全光谱拟合，用定制管道得出关键物理参数，通过模拟光谱量化测量可靠性与不确定性，评估光谱拟合性能，验证恒星质量估计，其增值目录为星系演化统计研究及未来分析提供基础。
中文摘要 AI 辅助
我们基于对约670万个星系光谱的全光谱拟合，对暗能量光谱仪（DESI）数据发布1（DR1）亮星系巡天（BGS）中的星系物理性质进行了全面分析。使用定制的光谱拟合管道，我们得出了包括恒星质量、恒星速度弥散、恒星族群年龄、尘埃消光和发射线性质等关键物理参数。为了量化测量的可靠性和系统不确定性，我们构建了大量模拟光谱，紧密再现了DESI数据的观测特性，包括现实的噪声和光谱特征。通过将恢复的参数与已知输入进行比较，我们评估了光谱拟合作为恒星连续谱信噪比（S/N，定义为中值连续谱通量与其相关误差的比值）和红移的函数的性能。我们发现，对于S/N≥5的光谱，恒星质量可以以可忽略的偏差稳健恢复，而低S/N光谱（S/N≤5）显示出约0.1 dex的轻微系统高估和散射增加。恒星族群参数也观察到类似趋势，而发射线通量则以高精度和最小偏差恢复。我们通过与光度光谱能量分布拟合的独立测量进行比较，进一步验证了我们的恒星质量估计，发现在预期的系统不确定性范围内总体一致性良好。这项工作中提出的增值目录使得能够利用DESI对星系演化进行广泛的统计研究，并为未来的分析提供了基础。
英文摘要
We present a comprehensive analysis of the physical properties of galaxies in the Dark Energy Spectroscopic Instrument (DESI) Data Release 1 (DR1) Bright Galaxy Survey (BGS), based on full spectral fitting of $\sim 6.7$ million galaxy spectra. Using a customized spectral fitting pipeline, we derive key physical parameters including stellar mass, stellar velocity dispersion, stellar population age, dust attenuation, and emission-line properties. To quantify the reliability and systematic uncertainties of our measurements, we construct a large set of mock spectra that closely reproduce the observed properties of DESI data, including realistic noise and spectral features. By comparing the recovered parameters with the known inputs, we assess the performance of the spectral fitting as a function of stellar continuum signal-to-noise ratio (S/N, defined as the ratio of the median continuum flux to its associated error) and redshift. We find that stellar masses can be robustly recovered with negligible bias for spectra with $\mathrm{S/N} \gtrsim 5$, while low-S/N spectra ($\mathrm{S/N} \lesssim 5$) show a mild systematic overestimation of $\sim 0.1$ dex and increased scatter. Similar trends are observed for stellar population parameters, while emission-line fluxes are recovered with high accuracy and minimal bias. We further validate our stellar mass estimates by comparison with independent measurements from photometric spectral energy distribution fitting, finding good overall consistency within the expected systematic uncertainties. The value-added catalog presented in this work enables a wide range of statistical studies of galaxy evolution with DESI, and provides a foundation for future analyses.
