We present a map of the total intrinsic reddening across ~34 deg$^{2}$ of the Small Magellanic Cloud (SMC) derived using optical ($ugriz$) and near-infrared (IR; $YJK_{\mathrm{s}}$) spectral energy distributions (SEDs) of background galaxies. The reddening map is created using a subsample of 29,274 galaxies with low levels of intrinsic reddening based on the LePhare $\chi^{2}$ minimisation SED-fitting routine. We find statistically significant enhanced levels of reddening associated with the main body of the SMC compared with regions in the outskirts [$\Delta E(B-V)\simeq 0.3$ mag]. A comparison with literature reddening maps of the SMC shows that, after correcting for differences in the volume of the SMC sampled, there is good agreement between our results and maps created using young stars. In contrast, we find significant discrepancies between our results and maps created using old stars or based on longer wavelength far-IR dust emission that could stem from biased samples in the former and uncertainties in the far-IR emissivity and the optical properties of the dust grains in the latter. This study represents one of the first large-scale categorisations of extragalactic sources behind the SMC and as such we provide the LePhare outputs for our full sample of ~500,000 sources.

中文翻译：

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背景星系追踪的麦哲伦星云的内在变红 – II. 小麦哲伦云

我们展示了使用光学 ($ugriz$) 和近红外 (IR; $YJK_{\mathrm{s} }$) 背景星系的光谱能量分布 (SED)。基于 LePhare $\chi^{2}$ 最小化 SED 拟合例程，使用 29,274 个星系的子样本创建红化地图，这些星系具有低水平的内在红化。我们发现与郊区 [$\Delta E(BV)\simeq 0.3$ mag] 相比，与 SMC 主体相关的发红程度在统计学上显着增强。与 SMC 的文献红化图的比较表明，在校正采样的 SMC 体积差异后，我们的结果与使用年轻恒星创建的图之间存在良好的一致性。相比之下，我们发现我们的结果与使用旧恒星或基于更长波长的远红外尘埃发射的地图之间存在显着差异，这可能源于前者的样本偏差以及远红外发射率和尘埃颗粒光学特性的不确定性后者。这项研究代表了 SMC 背后的首批大规模河外源分类之一，因此我们为我们约 500,000 个源的完整样本提供 LePhare 输出。