AI 中文总结
该研究量化了测光-运动学位置角错位对DESI-TF距离估算的系统不确定性，分析215个邻近星系后给出不同情况下的距离不确定性建议，为DESI-PV巡天的距离估算提供误差约束。
AI 中文摘要
Tully-Fisher（TF）关系是用于估算旋涡星系距离的经验工具。暗能量光谱仪（DESI）本动速度（PV）巡天利用`tractor`测光位置角，沿星系的半长轴放置光纤，为约53000个旋涡星系推断最大旋转速度。若测光位置角与速度场的运动学位置角不一致，会产生系统误差。我们量化了测光位置角对DESI-TF距离估算的系统不确定性，并评估测光-运动学位置角错位的影响。我们分析了来自PISCO和AMUSING巡天的215个邻近星系，在0.4R₂₆处估算最大旋转速度，以与DESI-PV保持一致。运动学参数使用`Cappellari Software`中的`PaFit`推导。全局测光参数依赖于锡耶纳星系星表SGA-2020的`tractor`数据，同时以`HostPhot`作为替代方法。我们的样本中约28%的星系测光-运动学位置角错位超过10°。距离的中位偏差约为+1.98 Mpc，残差分布存在偏斜的异常值。整体距离标准差为19.35 Mpc，错位星系的离散度是对齐星系的两倍。平均百分比误差为2.8%±1.96（标准误）。DESI-TF距离存在高星系间散射，尤其在错位系统中。由于DESI-TF目标缺乏运动学位置角测量，我们建议全局分数不确定性约为3.5%；当运动学信息可用时，错位小于10°的对齐星系不确定性约为1%，而严重错位或不完整系统的不确定性上限约为10%。
英文摘要
The Tully--Fisher (TF) relation is an empirical tool for estimating distances to spiral galaxies. The Dark Energy Spectroscopic Instrument (DESI) Peculiar Velocity (PV) Survey uses \texttt{`tractor'} photometric position angles to place fibers along the galaxy's semi-major axis and infer maximum rotational velocities for $\approx$ 53,000 spirals. Systematic errors arise if the photometric PA differs from the kinematic PA from velocity fields. We quantify systematic uncertainties in DESI-TF distance estimates from photometric PAs and assess the impact of photometric--kinematic PA misalignments. We analyze 215 nearby galaxies from the PISCO and AMUSING surveys, estimating maximum rotational velocities at $0.4\,R_{26}$ for consistency with DESI-PV. Kinematic parameters are derived using \texttt{`PaFit'} from \texttt{`Cappellari Software'}. Global photometric parameters rely on Siena Galaxy Atlas SGA-2020 \texttt{`tractor'} data, with \texttt{`HostPhot'} as an alternative approach. Approximately $28\%$ of our sample exhibit photometric--kinematic PA misalignments $>10^\circ$. The median bias in distance is $\approx +1.98\,\mathrm{Mpc}$ with a skewed residual distribution of outliers. The overall distance standard deviation is $19.35\,\mathrm{Mpc}$, with misaligned galaxies showing twice the dispersion of aligned ones. The Mean Percentage Error is $2.8\% \pm 1.96$ (SE). High galaxy-to-galaxy scatter appears in DESI-TF distances, particularly for misaligned systems. Because DESI-TF targets lack kinematic PA measurements, we recommend a global fractional uncertainty of $\approx 3.5\%$. When kinematic information is available, aligned galaxies with offsets $<10^\circ$ are consistent with $\approx 1\%$ uncertainty, while strongly misaligned or incomplete systems warrant an upper threshold of $\approx 10\%$.
CommentsAccepted for publication in A&A
