Evidence for C ii diffuse line emission at redshift z ∼ 2.6
Evidence for C ii diffuse line emission at redshift z ∼ 2.6
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DOI：
10.1093/mnrasl/slz126
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发表时间：
2019-04
影响因子：
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通讯作者：
Shengqi Yang;A. Pullen;E. Switzer
中科院分区：
文献类型：
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作者：
Shengqi Yang;A. Pullen;E. Switzer
C II是恒星形成星系最亮的发射线之一，是恒星形成的极佳示踪剂。最近的工作测量了红移2<；z<；3.2的C II发射线幅度，通过将普朗克高频仪器发射地图与来自重子振荡光谱天空调查的超密度示踪剂进行交叉关联，发现${i}_{\Text C}\，\rm{\Small II}}=6.6^{+5.0}_{-4.8}\x{10}^{4}$Jy SR−1在$95\，{\Text{%}}$置信度水平。在本文中，我们通过改进每个普朗克频段中的掩码权重和协方差矩阵中的精度来改进这一早期工作。我们在545 GHz普朗克频段探测到了超额辐射，而不是存在于353-857 GHz普朗克频段的宇宙红外背景(CIB)。这与红移的CⅡ发射是一致的，在这种情况下，在95美元的置信度水平下，我们报告了$b{\Text C}，\rm{\Small II}}i_{{\Text C}\，\Rm{\Small II}}=2.0^{+1.2}_{-1.1}\×10^5$Jy sr−1，这强烈支持多种C II发射的碰撞激发模型。我们的探测显示了具有非零C II参数的模型的强有力的证据，尽管需要在高光谱分辨率下的线强度映射观测来证实这一结果。
C ii is one of the brightest emission lines from star-forming galaxies and is an excellent tracer for star formation. Recent work measured the C ii emission line amplitude for redshifts 2 < z < 3.2 by cross-correlating Planck High Frequency Instrument emission maps with tracers of overdensity from the Baryon Oscillation Spectroscopic Sky Survey, finding ${I}_{{\text C}\,\rm {\small II}}=6.6^{+5.0}_{-4.8}\times {10}^{4}$ Jy sr−1 at $95\,{\text{per cent}}$ confidence level. In this paper, we present a refinement of this earlier work by improving the mask weighting in each of the Planck bands and the precision in the covariance matrix. We report a detection of excess emission in the 545 GHz Planck band separate from the cosmic infrared background (CIB) present in the 353–857 GHz Planck bands. This excess is consistent with redshifted C ii emission, in which case we report $b_{{\text C} \,\rm {\small II}}I_{{\text C} \,\rm {\small II}} =2.0^{+1.2}_{-1.1}\times 10^5$ Jy sr−1 at $95\ {\text {per cent}}$ confidence level, which strongly favours many collisional excitation models of C ii emission. Our detection shows strong evidence for a model with a non-zero C ii parameter, though line intensity mapping observations at high spectral resolution will be needed to confirm this result.