改进盖亚波段中造父变星的红化估计：一种机器学习方法用于 PAC(Z) 关系
Improving reddening estimates for RR Lyrae stars in the Gaia bands: a machine learning approach to the PAC(Z) relation
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中文总结 AI 辅助
研究旨在重新校准盖亚波段中 RRab 星消光关系并建立 RRc 星类似关系，采用盖亚 DR3 测光等数据，通过机器学习方法得出新关系，能可靠估计消光，改进 DR3 实现，为银河系研究提供工具。
中文摘要 AI 辅助
造父变星是古老恒星群体的重要示踪剂和银河系及附近星系的距离指示器。然而，它们作为标准烛光的使用受到消光不确定性的限制，特别是在盖亚波段。在盖亚 DR3 中，基模造父变星（RRab）的吸收值（AG）基于在小样本上校准的经验周期 - 振幅 - 颜色（PAC）关系和通带变换。我们旨在重新校准 RRab 星的消光关系，并首次在盖亚通带中建立第一泛音造父变星（RRc）的类似关系。我们使用了盖亚 DR3 测光和全天空参考样本的脉动特性。通过顺序特征选择结合线性回归和自助重采样得出固有颜色（G - GRP）0 和（GBP - GRP）0，确保对颜色过量和 AG 的稳健估计。我们重新校准了 RRab 星的 PACZ 关系，并首次得出了盖亚波段中 RRc 星的 PAC 关系。新关系以约 0.03 - 0.04 星等的残余散射再现固有颜色，并提供两种脉动类型的 AG 估计。对银河系球状星团和矮星系中的造父变星测试显示 AG 值一致，基于（GBP - GRP）的 PAC(Z) 关系比使用（G - GRP）的更稳定。新关系为 RRab 和 RRc 星提供了可靠的消光估计，改进了 DR3 的实现，并为盖亚 DR4 的银河系研究提供了有价值的工具。
英文摘要
RR Lyrae stars are essential tracers of old stellar populations and distance indicators across the Milky Way and nearby galaxies. However, their use as standard candles is limited by uncertainties in extinction, especially in the Gaia bands. In Gaia DR3, absorption values (AG) for fundamental-mode RR Lyrae (RRab) were based on an empirical period-amplitude-color (PAC) relation calibrated on a small sample and on passband transformations. We aim to recalibrate extinction relations for RRab stars and establish, for the first time, analogous relations for first-overtone RR Lyrae (RRc) stars in the Gaia passbands. We used Gaia DR3 photometry and pulsation properties of an all-sky reference sample. Intrinsic colors (G - GRP)0 and (GBP - GRP)0 were derived through sequential feature selection combined with linear regression and bootstrap resampling, ensuring robust estimates of color excess and AG. We recalibrated PACZ relations for RRab stars and derived, for the first time, PAC relations for RRc stars in the Gaia bands. The new relations reproduce intrinsic colors with residual scatters of ~0.03-0.04 mag and provide AG estimates across both pulsation types. Tests on RR Lyrae stars in Galactic globular clusters and dwarf galaxies show consistent AG values, with the PAC(Z) relations based on (GBP - GRP) being more stable than those using (G - GRP). The new relations provide reliable extinction estimates for both RRab and RRc stars, improving on the DR3 implementation and offering a valuable tool for Galactic studies in view of Gaia DR4.
