AI 中文总结
该研究利用Zooniverse平台开展公民科学项目，从49703个星系中识别出数千个水母星系等候选星系，证实冲压剥离比例随星系团质量增加而上升，验证公民科学可可靠识别经历环境过程的星系并发布分类数据集。
AI 中文摘要
目标：我们展示了“寻找水母星系”的首批成果，这是一个利用Zooniverse平台识别正在经历冲压剥离（RPS）的星系的试点公民科学项目。方法：志愿者对暗能量相机遗产巡天（Dark Energy Camera Legacy Survey）中晚型星系的彩色图像进行目视检查，样本包含49703个星系，这些星系均位于星系团和星系群的4倍$R_{500}$范围内，且g和r波段亮度亮于19等、半光半径不小于2角秒，以辅助分类。我们详细说明数据处理过程，包括对分类结果去偏、优化投票分数阈值以最大化完整性和纯度，该阈值通过一组预先标记的真实星系集进行校准。结果：我们的最终星表包含6739个水母候选星系（其中6621个为新发现）、5430个并合候选星系和29729个未受扰动的星系，其中3910个水母星系呈现明显的尾状形态。我们发现，冲压剥离候选星系的比例从星系群中的约10%上升到大质量星系团中的20%-30%，证实了此前基于较小样本的研究结果。对于我们冲压剥离候选样本中拥有光谱数据的子集，我们测量到其到星系团中心的中位速度比星系团总体高53%，与处于星系团吸积早期阶段的星系一致；这些星系通常为晚型蓝色星系，恒星形成率较高，符合预期。这些结果表明公民科学家能够可靠识别经历环境过程的星系，我们发布了37599个经目视分类的星系初始数据集，作为未来研究星系团中星系演化的资源。
英文摘要
Aims: We present the first results of Fishing for Jellyfish Galaxies, a pilot citizen-science project using Zooniverse to identify galaxies undergoing ram-pressure stripping (RPS). Methods: Volunteers visually inspected colour images of late-type galaxies from the Dark Energy Camera Legacy Survey, from a sample of 49,703 galaxies selected within $4 \times R_{500}$ of clusters and groups, restricted to galaxies brighter than 19th magnitude in the g and r bands, and with a minimum half-light radius of 2 arcseconds, to aid classification. We detail our data processing, including debiasing classifications and optimising vote-fraction thresholds to maximise completeness and purity, calibrated against a ground-truth set of pre-labelled galaxies. Results: Our final catalogue contains 6739 jellyfish candidates (6621 new), 5430 merger candidates, and 29,729 undisturbed galaxies, with 3910 jellyfish exhibiting prominent tail-like morphologies. We find that the fraction of RPS candidates rises from ~10% in galaxy groups to ~20-30% in massive clusters, confirming the findings of previous studies carried out on smaller samples. For the subset of our RPS candidate sample with spectroscopic data, we measure a median clustercentric velocity 53% higher than the general cluster population, consistent with galaxies in early stages of accretion into the cluster. They are also typically late-type blue galaxies with elevated star-formation rates, in agreement with expectations. These results demonstrate that citizen scientists can reliably identify galaxies that undergo environmental processes. We provide the initial release of 37,599 visually classified galaxies as a resource for future studies of galaxy transformation in clusters.
Comments13 pages, 12 figures, 2 tables
