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arXiv 2307.00367astro-ph.GA
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暗尘埃 III:高质量单云消光曲线样本。审视银河系中的消光曲线

Dark Dust III: The high-quality single-cloud reddening curve sample. Scrutinizing extinction curves in the Milky Way

R. Siebenmorgen, J. Smoker, J. Krełowski, Karl Gordon, Rolf Chini

AI总结:

本研究通过多步质量筛选构建了目前最高质量的银河系单云消光曲线样本,测得平均R_V为3.1±0.4,为后续暗尘埃性质研究提供基础。

摘要:

弥漫星际介质中的尘埃本质可通过消光曲线得到最佳研究,这类曲线对应的观测者与背景源之间仅存在一片星际云。已发表的消光曲线往往存在各类系统不确定性。我们合并了895条恒星消光曲线样本,这些恒星同时具备FORS2偏振光谱与UVES高分辨率光谱。最终得到的111条指向OB型恒星的视线拥有175条消光曲线。对于这些恒星,我们通过UVES高分辨率光谱确定了它们的光谱型。为获取高质量消光曲线,我们排除了IUE/FUSE数据中因多星系统导致光谱复合的恒星;同样,我们省略了光谱型分类不确定的恒星或具有光变的恒星;我们还忽略了GAIA的DR2与DR3视差数据不一致的恒星。最后,我们识别出空间与地面设备推导的消光曲线在0.28μm至U波段或R_V值上存在差异的恒星。总计,我们发现53颗恒星的一条或多条消光曲线通过了剔除标准,这构成了目前可用的最高质量银河系消光曲线样本。对我们高质量样本的曲线取平均后,得到R_V = 3.1 ± 0.4,证实了此前的估计。本系列的后续论文将使用当前的精确消光曲线样本,结合偏振数据来研究暗尘埃的性质。

英文摘要:

The nature of dust in the diffuse interstellar medium can be best investigated by means of reddening curves where only a single interstellar cloud lies between the observer and the background source. Published reddening curves often suffer from various systematic uncertainties. We merge a sample of 895 reddening curves of stars for which both FORS2 polarisation spectra and UVES high-resolution spectra are available. The resulting 111 sightlines toward OB-type stars have 175 reddening curves. For these stars, we derive their spectral type from the UVES high-resolution spectroscopy. To obtain high-quality reddening curves we exclude stars with composite spectra in the IUE/FUSE data due to multiple stellar systems. Likewise, we omit stars that have uncertain spectral type designations or stars with photometric variability. We neglect stars that show inconsistent parallaxes when comparing DR2 and DR3 from GAIA. Finally, we identify stars that show differences in the space and ground-based derived reddening curves between $0.28\,μ$m and the $U$-band or in $R_V$. In total, we find 53 stars with one or more reddening curves passing the rejection criteria. This provides the highest quality Milky Way reddening curve sample available today. Averaging the curves from our high-quality sample, we find $R_V = 3.1 \pm 0.4$, confirming previous estimates. A future paper in this series will use the current sample of precise reddening curves and combine them with polarisation data to study the properties of Dark Dust.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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