论文标题
成像和恒星运动学在识别星系合并残留物中的结合和各自的作用
The combined and respective roles of imaging and stellar kinematics in identifying galaxy merger remnants
论文作者
论文摘要
确定合并在星系进化中的作用的主要挑战之一是选择纯净和完整的合并样本。特别是，虽然可以通过光谱标准相对轻松地获得大型且合理的相互作用的星系对样品，但自动选择后钙化后的合并残留物仅限于单独的残留物的物理特征。此外，这种选择主要集中在成像数据上 - 而运动学数据可能为识别合并残留物提供了免费的基础。因此，我们研究了合并残留物在区分星系合并残留物与其他星系时的形态和运动学特征的理论实用性。使用理想化的合成图像和视线线的恒星速度图对深度分类模型进行校准和评估，该图形的星系群和来自TNG100宇宙流体动力学模拟的合并群体和合并残留物。我们表明，即使是理想化的恒星运动学数据，与成像和表现不佳相比，完整性的成像和表现不佳的$ 2.1 \％\ pm0.5 \％$，对于我们的trducial Model架构，即使是$ 4.7 \％\％\％\％\％\％\％\％\％\％$。组合成像和恒星运动学的完整性可提高（$ 1.8 \％\ pm0.4 \％\％$，而$ 92.7 \％\％\％\％\ pm0.2 \％$单独从成像中获得），但纯度没有变化，但$ 0.1 \％\％\％\％\ pm0.3 \％$ pm的$ 92.72.72.72.72.72.72.72.72.72.72.72.72.72.72.2.22.72.7 \％2.22残留和非赔偿控制星系）。所有模型的分类准确性尤其敏感，以分离$ \ Lessim40 $ kpc和时间 - 钙化。综上所述，我们的结果表明，在异质星系种群中，恒星运动学数据对合并残留识别的成像几乎没有提供。
One of the central challenges to establishing the role of mergers in galaxy evolution is the selection of pure and complete merger samples in observations. In particular, while large and reasonably pure interacting galaxy pair samples can be obtained with relative ease via spectroscopic criteria, automated selection of post-coalescence merger remnants is restricted to the physical characteristics of remnants alone. Furthermore, such selection has predominantly focused on imaging data -- whereas kinematic data may offer a complimentary basis for identifying merger remnants. Therefore, we examine the theoretical utility of both the morphological and kinematic features of merger remnants in distinguishing galaxy merger remnants from other galaxies. Deep classification models are calibrated and evaluated using idealized synthetic images and line-of-sight stellar velocity maps of a heterogeneous population of galaxies and merger remnants from the TNG100 cosmological hydrodynamical simulation. We show that even idealized stellar kinematic data has limited utility compared to imaging and under-performs by $2.1\%\pm0.5\%$ in completeness and $4.7\%\pm0.4\%$ in purity for our fiducial model architecture. Combining imaging and stellar kinematics offers a small boost in completeness (by $1.8\%\pm0.4\%$, compared to $92.7\%\pm0.2\%$ from imaging alone) but no change in purity ($0.1\%\pm0.3\%$ improvement compared to $92.7\%\pm0.2\%$, evaluated with equal numbers of merger remnant and non-remnant control galaxies). Classification accuracy of all models is particularly sensitive to physical companions at separations $\lesssim40$ kpc and to time-since-coalescence. Taken together, our results show that the stellar kinematic data has little to offer in compliment to imaging for merger remnant identification in a heterogeneous galaxy population.
