论文标题

来自老板和虹膜的弥漫性银河光的光谱

An Optical Spectrum of the Diffuse Galactic Light from BOSS and IRIS

论文作者

Chellew, Blake, Brandt, Timothy D., Hensley, Brandon S., Draine, Bruce T., Matthaey, Eve

论文摘要

我们介绍了3700至10,000 a之间的弥漫性银河光(DGL),该光谱是通过将光学天空强度与远红外灰尘发射相关联获得的。我们使用了来自Boss/SDSS-III的近25万间空白光谱,以及来自IRAS卫星的IRIS重新处理的地图。与SDSS-II相比,较大的样本量导致两个信号增加到噪声。我们将这些数据集与光学/远红外相关的模型相结合,该模型解释了灰尘自我吸收。 DGL的光谱特征与恒星光谱中的特征非常吻合。有证据表明,北部和南部银半球的老板覆盖的地区之间的DGL连续体有所不同。我们解释了由于恒星种群差异而导致的红色波长的差异,这两个地区主要是旧星星,但南部的年轻恒星的较高部分。南部DGL频谱的预测也有很大的过量,而北部没有明显的辐射转移模型。我们将其解释为以〜6500 a为中心,以延长红发射(ERE)形式的发光证据。观察到的4000 a断裂的强度表明,在4000 a时最多约7%的尘埃光可能是由于蓝色发光。我们的DGL光谱对尘埃散射和发光提供了限制,而与灭绝的测量无关。

We present a spectrum of the diffuse Galactic light (DGL) between 3700 and 10,000 A, obtained by correlating optical sky intensity with far-infrared dust emission. We use nearly 250,000 blank-sky spectra from BOSS/SDSS-III together with IRIS-reprocessed maps from the IRAS satellite. The larger sample size compared to SDSS-II results in a factor-of-two increase in signal to noise. We combine these data sets with a model for the optical/far-infrared correlation that accounts for self-absorption by dust. The spectral features of the DGL agree remarkably well with features present in stellar spectra. There is evidence for a difference in the DGL continuum between the regions covered by BOSS in the northern and southern Galactic hemisphere. We interpret the difference at red wavelengths as the result of a difference in stellar populations, with mainly old stars in both regions but a higher fraction of young stars in the south. There is also a broad excess in the southern DGL spectrum over the prediction of a simple radiative transfer model, without a clear counterpart in the north. We interpret this excess, centered at ~6500 A, as evidence for luminescence in the form of extended red emission (ERE). The observed strength of the 4000 A break indicates that at most ~7% of the dust-correlated light at 4000 A can be due to blue luminescence. Our DGL spectrum provides constraints on dust scattering and luminescence independent of measurements of extinction.

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