类银河系星系的形态统计
Morphological Statistic of Milky Way-like Galaxies
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中文总结 AI 辅助
本研究统计了1,738个类银河系星系的旋臂形态，发现多臂系统占主导，且银河系内两臂外多臂结构（含分叉）与典型多臂星系一致。
中文摘要 AI 辅助
我们利用斯隆数字巡天和数字化巡天的多波段光学图像，分析了1,738个与银河系哈勃类型相近的近邻星系（$i<60^\circ$，$z<0.048$）的旋臂形态。多臂系统占主导地位，约占样本的50-60%，占大星系（$d_{\rm max} \geqslant 18~\mathrm{kpc}$）的约75%。在$90\pm3$%的多臂星系中，两条内臂延伸为多条外臂；三臂内结构占$9\pm2$%，四臂或更多臂的情况罕见（$<1$%）。形态和内臂数量在不同波段间的一致性约为80%。分叉点标志着从两条内臂向多条外臂的过渡，出现在多达约40%的星系中，在追踪较年轻恒星族的更蓝波段中更为突出，并聚集在距星系中心4-7千秒差距的范围内。这些统计结果表明，银河系的内两臂和外多臂形态，包括在相似半径处的分叉，与典型多臂旋涡星系的形态大体一致。
英文摘要
We analyze the spiral morphology of 1,738 nearby galaxies with similar Hubble type of the Milky Way ($i<60^\circ$, $z<0.048$) using multi-band optical images from the Sloan Digital Sky Survey and Digitized Sky Survey. Multiple-arm systems dominate, comprising $\sim$50-60% of the sample and $\sim$75% of large galaxies ($d_{\rm max} \geqslant 18~\mathrm{kpc}$). In $90\pm3$% of multiple-arm galaxies, two inner arms extend into multiple outer arms; three-arm inner structures occur in $9\pm2$%, and four or more are rare ($<1$%). Morphology and inner-arm counts are consistent across bands at $\sim$80%. Bifurcation points, marking the transition from two inner arms to multiple outer arms, occur in up to $\sim$40% of galaxies, are more prominent in bluer bands tracing younger stellar populations, and cluster within 4-7~kpc of galaxy centers. These statistics suggest that the Milky Way's inner two-arm and outer multiple-arm morphology, including bifurcations at similar radii, is broadly consistent with that of a typical multiple-arm spiral galaxy.
发表机构
- Purple Mountain Observatory, Chinese Academy of Sciences（中国科学院紫金山天文台）
- School of Astronomy and Space Science, University of Science and Technology of China（中国科学技术大学天文与空间科学学院）
- Three Gorges University（三峡大学）
- National Astronomical Observatories, Chinese Academy of Sciences（中国科学院国家天文台）
- School of Astronomy and Space Science, University of Chinese Academy of Sciences（中国科学院大学天文与空间科学学院）
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