漩涡星系中大质量食双星的天体普查
A census of massive eclipsing binaries in the Whirlpool Galaxy
- California Institute of Technology（加州理工学院）
- The Observatories of the Carnegie Institution for Science（卡内基科学研究所天文台）
- University of California, Berkeley（加州大学伯克利分校）
- Miller Institute for Basic Research, University of California Berkeley（加州大学伯克利分校米勒基础研究所）
- Center for Astrophysics — Harvard & Smithsonian（哈佛-史密森尼天体物理中心）
机构由 AI 辅助整理，请以论文原文为准。
中文总结 AI 辅助
利用HST多历元测光数据，在M51中识别出173个大质量食双星候选体，通过光变曲线与能谱拟合推断其性质，并统计得到密近双星比例约27%，表明其形成对金属丰度依赖较弱。
中文摘要 AI 辅助
我们呈现了漩涡星系（M51）中大质量食双星（EB）候选体的天体普查。M51是一个距离7.5 Mpc、金属丰度约为太阳丰度（$Z\sim Z_\odot$）的正面朝向旋涡星系。利用34个历元的红波段哈勃太空望远镜（HST）测光数据和单一历元的宽波段紫外-光学测光数据，我们识别出173个大质量食双星候选体（质量$>5~{\rm M_\odot}$），其轨道周期$P_{\rm orb}$为1-30天。该样本追踪了M51旋臂上的年轻恒星种群。对136个系统进行的联合光变曲线和光谱能量分布拟合，得到了有效温度$T_{\rm eff}=10{,}000$-$50{,}000$ K、半径$R=7$-$66~{\rm R_\odot}$、质量$5$-$120~{\rm M_\odot}$的双星系统。我们使用详细的注入-恢复模拟来量化巡天的完备性，并推断大质量双星种群的固有性质。在种群层面，我们推断出在$2\leq P_{\rm orb}/{\rm d}<20$和$0.1\leq q\leq1$范围内，密近双星比例为$f_{\rm close}=27.4\pm7.1\\%$。在同一周期范围内，固有周期分布与对数均匀分布一致，即${\rm d}N/{\rm d}\log P_{\rm orb}\propto P_{\rm orb}^{\pi}$，其中$\pi=0.29\pm0.32$。这些统计特征与银河系、大麦哲伦云（LMC）和小麦哲伦云（SMC）中的大质量恒星种群大体匹配，并初步显示出在较低金属丰度下密近双星比例较低的趋势。在这些星系所覆盖的约$0.2$-$1.1~Z_\odot$范围内，总体相似性表明密近大质量双星的形成对金属丰度的依赖性较弱。我们的巡天确立了食双星作为测量本星系群之外大质量双星种群的有力工具，并为M51中约10万颗亮星和变星提供了丰富的全波段天体普查。
英文摘要
We present a census of massive eclipsing binary (EB) candidates in the Whirlpool Galaxy (M51), a face-on spiral galaxy at 7.5 Mpc with $Z\sim Z_\odot$. Using 34 epochs of red-optical Hubble Space Telescope (HST) photometry and a single epoch of broadband UV-optical photometry, we identify 173 massive EB candidates ($>5~{\rm M_\odot}$) with orbital periods $P_{\rm orb}$=1-30 days. The sample traces young stellar populations across the spiral arms of M51. Joint light-curve and spectral energy distribution fits for 136 systems yield binaries spanning $T_{\rm eff}=10{,}000$-$50{,}000$ K, $R=7$-$66~{\rm R_\odot}$, and masses of $5$-$120~{\rm M_\odot}$. We use detailed injection-recovery simulations to quantify the survey's completeness and infer intrinsic properties of the massive binary population. At the population level, we infer a close-binary fraction of $f_{\rm close}=27.4\pm7.1\%$ for $2\leq P_{\rm orb}/{\rm d}<20$ and $0.1\leq q\leq1$. Over the same period range, the intrinsic period distribution is consistent with being log-uniform, ${\rm d}N/{\rm d}\log P_{\rm orb}\propto P_{\rm orb}^π$ with $π=0.29\pm0.32$. These demographics broadly match those of massive-star populations in the Milky Way, LMC, and SMC, with tentative evidence for a lower close-binary fraction at lower metallicity. Across the $\sim0.2$-$1.1~Z_\odot$ range spanned by these galaxies, the overall similarities suggest that the formation of close massive binaries depends only weakly on metallicity. Our survey establishes EBs as a powerful tool for measuring massive-binary demographics beyond the Local Group and provides a rich panchromatic census of $\sim$100,000 luminous stars and variables in M51.
