We used existing data from the New Horizons LORRI camera to measure the optical-band ($0.4\lesssim\lambda\lesssim0.9{\rm\mu m}$) sky brightness within seven high galactic latitude fields. The average raw level measured while New Horizons was 42 to 45 AU from the Sun is $33.2\pm0.5{\rm ~nW ~m^{-2} ~sr^{-1}}.$ This is $\sim10\times$ darker than the darkest sky accessible to the {\it Hubble Space Telescope}, highlighting the utility of New Horizons for detecting the cosmic optical background (COB). Isolating the COB contribution to the raw total requires subtracting scattered light from bright stars and galaxies, faint stars below the photometric detection-limit within the fields, and diffuse Milky Way light scattered by infrared cirrus. We remove newly identified residual zodiacal light from the IRIS $100\mu$m all sky maps to generate two different estimates for the diffuse galactic light (DGL). Using these yields a highly significant detection of the COB in the range ${\rm 15.9\pm 4.2\ (1.8~stat., 3.7~sys.) ~nW ~m^{-2} ~sr^{-1}}$ to ${\rm 18.7\pm 3.8\ (1.8~stat., 3.3 ~sys.)~ nW ~m^{-2} ~sr^{-1}}$ at the LORRI pivot wavelength of 0.608 $\mu$m. Subtraction of the integrated light of galaxies (IGL) fainter than the photometric detection-limit from the total COB level leaves a diffuse flux component of unknown origin in the range ${\rm 8.8\pm4.9\ (1.8 ~stat., 4.5 ~sys.) ~nW ~m^{-2} ~sr^{-1}}$ to ${\rm 11.9\pm4.6\ (1.8 ~stat., 4.2 ~sys.) ~nW ~m^{-2} ~sr^{-1}}$. Explaining it with undetected galaxies requires the galaxy-count faint-end slope to steepen markedly at $V>24$ or that existing surveys are missing half the galaxies with $V< 30.$

中文翻译：

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宇宙光学背景的新视野观测

我们使用来自 New Horizo​​ns LORRI 相机的现有数据来测量七个高银河纬度区域内的光学波段 ($0.4\lesssim\lambda\lesssim0.9{\rm\mu m}$) 天空亮度。新视野号距离太阳 42 到 45 天文单位时测得的平均原始水平为 $33.2\pm0.5{\rm ~nW ~m^{-2} ~sr^{-1}}。这是 $\sim10\比 {\it Hubble Space Telescope} 所能到达的最黑暗的天空还要暗，突出了 New Horizo​​ns 在探测宇宙光学背景 (COB) 方面的效用。隔离 COB 对原始总量的贡献需要减去来自明亮恒星和星系的散射光、场内低于光度检测极限的昏暗恒星以及被红外卷云散射的漫射银河光。我们从 IRIS $100\mu$m 的所有天空图中删除了新识别的残余黄道光，以生成两种不同的漫射银河光 (DGL) 估计值。使用这些可以在 ${\rm 15.9\pm 4.2\ (1.8~stat., 3.7~sys.) ~nW ~m^{-2} ~sr^{-1}} 范围内对 COB 进行非常重要的检测$ 到 ${\rm 18.7\pm 3.8\ (1.8~stat., 3.3 ~sys.)~ nW ~m^{-2} ~sr^{-1}}$ 在 LORRI 枢轴波长为 0.608 $\mu $米。从总 COB 水平减去比光度检测限更暗的星系的积分光 (IGL)，留下一个来源不明的漫射通量分量，范围为 ${\rm 8.8\pm4.9\ (1.8 ~stat., 4.5 ~sys.) ~nW ~m^{-2} ~sr^{-1}}$ 到 ${\rm 11.9\pm4.6\ (1.8 ~stat., 4.2 ~sys.) ~nW ~m^{ -2} ~sr^{-1}}$。用未被探测到的星系来解释它需要星系计数的暗端斜率在 $V> 处显着变陡。