FAST 极深巡天：FUDS0 天区中的重子 Tully-Fisher 关系
FAST Ultra-Deep Survey: the baryonic Tully-Fisher relation in FUDS0 field
浏览论文内容
中文总结 AI 辅助
本研究基于 FAST 极深巡天先导天区 FUDS0 的星系，探究红移至 0.42 的重子 Tully-Fisher 关系，识别出两个成分，分析离群点起源，发现低红移区间无显著演化，完整巡天将提供更大样本以约束其演化。
中文摘要 AI 辅助
重子 Tully-Fisher 关系（BTFR）是本地宇宙中盘星系最紧密的标度关系之一，因此是研究星系形成与演化的重要工具。然而，由于本地宇宙以外的 HI 星系样本有限、光学推导的旋转曲线存在局限以及选择效应，人们对 BTFR 随宇宙时间的演化仍知之甚少。本研究从 FAST 极深巡天（FUDS）先导天区 FUDS0 中探测到的星系，探究红移最高达 $z=0.42$ 的 BTFR。如前期研究发现，我们在重子质量与旋转速度的平面中识别出两个成分：$C_{\rm BTFR}$（紧密成分）和 $C_{\rm Outlier}$（弥散成分）。我们采用高斯混合模型来拟合 BTFR，得到斜率 $k=3.32_{-0.11}^{+0.12}$、零点 $b=10.07_{-0.03}^{+0.03}$ 以及本征弥散 $\sigma_{\rm BTFR}=0.036_{-0.009}^{+0.010}$ 的最佳拟合参数。我们使用随机森林分类器探究离群成分的起源，发现低信号显著性和不准确的倾角是导致离群群体的关键因素，表明观测效应是其主要起源。我们在三个不同红移区间中检验演化趋势，两个低红移区间的斜率和零点均在 1-σ 不确定度范围内一致，说明无显著演化；最高红移区间中从 $C_{\rm Outlier}$ 成分间接推断的 BTFR 参数也与该结论吻合。正在进行的完整 FUDS 巡天将提供更大的样本，以对 BTFR 演化进行更精确的约束。
英文摘要
The Baryonic Tully-Fisher relation (BTFR) is one of the tightest scaling relations for disk galaxies in the local Universe, and therefore is an important tool for studying the fomation and evolution of galaxies. However, the evolution of the BTFR over cosmic time is poorly understood due to the limited sample of HI galaxies beyond the local Universe, limitations of optically-derived rotation curves, and selection effects. In this work, we explore the BTFR at redshifts up to $z=0.42$ from galaxies detected in the pilot FAST Ultra-Deep Survey (FUDS) field, FUDS0. As found in previous work, we identify two components in the plane of baryonic mass versus rotational velocity, $C_{\rm BTFR}$ (tight) and $C_{\rm Outlier}$ (dispersed). A Gaussian mixture model is employed to recover the BTFR, yielding the best fit parameters for the slope $k=3.32_{-0.11}^{+0.12}$, zero point $b=10.07_{-0.03}^{+0.03}$, and intrinsic scatter $σ_{\rm BTFR}=0.036_{-0.009}^{+0.010}$. A random forest classifier is used to investigate the origin of the outlier component. We find that low signal significance and inaccurate inclinations are the key factors that contribute to the outlier population, indicating that observational effects are the dominant origin. Evolutionary trends are examined in three different redshift bins. Both the slope and zero point show consistency within 1-$σ$ uncertainty in the two low redshift bins, indicating no significant evolution. The indirectly inferred BTFR parameters from the $C_{\rm Outlier}$ component in the highest redshift bin aligns with the conclusion. The ongoing full FUDS survey will provide a larger sample to enable more accurate constraints on BTFR evolution.
