利用1080万根DESI天空光纤获取的银河系弥散光的空间分辨光谱
Spatially-Resolved Spectra of Diffuse Galactic Light using 10.8 M DESI Sky Fibers
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中文总结 AI 辅助
该研究利用DESI 1080万根天空光纤的光谱数据，空间分辨测量银河系弥散光，发现新的散射信号与分子氢发射，绘制扩展红发射空间分布，为辐射传输研究提供观测约束。
中文摘要 AI 辅助
我们利用DESI第3年数据集中的1080万条“空白”天空光谱，通过与IRAS的远红外发射进行关联，在光谱分辨率R≈4000的光学波段测量银河系弥散光（DGL）光谱。将天空划分为54平方度的像素（HEALPix，NSIDE=8），我们在银纬较高的天区DESI覆盖范围内绘制了DGL关联光谱和星云发射线的变化。与之前基于SDSS的分析相比，数据量的增加使DGL领域有了多项新发现，包括中性星际钠和钾对视线方向的散射以及从视线方向的散射。我们还在近红外波段探测到分子氢的振转跃迁直接发射，其绝对辐射率为0.65±0.13/-0.12×10^-9 erg·cm^-2·s^-1·sr^-1，大致与理论预期一致，但正-仲线比率明显低0.60±0.28/-0.27倍。我们确认了之前对DGL中扩展红发射（ERE）的探测并绘制了其空间变化。我们的空间分辨DGL图为近期利用银河系三维模型开展的辐射传输研究提供了重要观测约束。
英文摘要
Using 10.8 million ``blank'' sky spectra from the DESI Year 3 dataset, we measure the diffuse galactic light (DGL) spectrum in the optical at spectral resolution $R \sim 4000$ by correlating with far-infrared emission from IRAS. Subdividing the sky into 54 deg$^2$ pixels (HEALPix, NSIDE = 8), we map the variation of the DGL correlation spectrum and nebular emission lines across the DESI footprint in the high-Galactic-latitude sky. The increased data volume over previous SDSS-based analyses enables several new detections in the DGL, including scattering both onto and out of the line of sight from neutral interstellar sodium and potassium. We further detect direct emission from ro-vibrational transitions of molecular hydrogen in the near-infrared with an absolute radiance of $0.65\substack{+0.13 \\ -0.12}\times10^{-9}~{\rm erg\, cm^{-2}\,s^{-1}\,sr^{-1}}$, roughly consistent with theoretical expectations, but with an apparent ortho-to-para line ratio that is lower by a factor of $0.60\substack{+0.28 \\ -0.27}$. We confirm previous detections of extended red emission (ERE) in the DGL and map its spatial variation. Our spatially resolved DGL maps provide important observational constraints for the radiative transfer efforts that are now possible with recent 3D models of the Milky Way.
发表机构
- Princeton University（普林斯顿大学）
- New Mexico State University（新墨西哥州立大学）
- Space Telescope Science Institute（太空望远镜科学研究所）
- NSF NOIRLab（美国国家光学红外天文研究实验室）
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