The MOSDEF Survey: The Variation of the Dust Attenuation Curve with Metallicity
The MOSDEF Survey: The Variation of the Dust Attenuation Curve with Metallicity
复制标题
DOI：
10.3847/1538-4357/aba35e
复制
发表时间：
2020-05
期刊：
影响因子：
--
通讯作者：
I. Shivaei;N. Reddy;G. Rieke;A. Shapley;M. Kriek;A. Battisti;B. Mobasher;R. Sanders;T. Fetherolf;Mojegan Azadi;A. Coil;W. Freeman;Laura de Groot;G. Leung;S. Price;B. Siana;T. Zick
中科院分区：
文献类型：
--
作者：
I. Shivaei;N. Reddy;G. Rieke;A. Shapley;M. Kriek;A. Battisti;B. Mobasher;R. Sanders;T. Fetherolf;Mojegan Azadi;A. Coil;W. Freeman;Laura de Groot;G. Leung;S. Price;B. Siana;T. Zick
我们导出了z = 1.4-2.6处星系的紫外光学星尘衰减曲线，它是气相金属丰度的函数。我们使用了218个恒星形成星系的样本，不包括那些非常年轻或恒星形成严重模糊的星系，这些星系来自MOSFIRE深度演化场调查，具有Hα， Hβ和[N ii]λ 6585光谱测量。我们用Balmer衰减量（即h α到h β光度）比较了被划分为尘埃遮蔽区的星系的平均通量密度，从而约束了衰减曲线的形状。高金属丰度样品的平均衰减曲线（对应于）有一个浅斜率，与Calzetti局部星暴曲线相同，并且有一个显著的UV 2175 Å消光凸起，其强度是银河系凸起的~ 0.5倍。另一方面，低金属丰度样品（）的平均衰减曲线斜率较SMC曲线陡，仅在3σ水平上与Calzetti斜率一致。在低金属丰度曲线中没有检测到紫外线凸起，这表明在低金属丰度曲线中相对缺乏引起凸起的小尘埃颗粒。此外，我们发现，对于金属丰度低的星系，星云的平均变红（E(B−V)）是恒星连续体的2倍，而对于金属丰度高的星系，星云和恒星的变红是相似的。后者可能是由于覆盖恒星形成区域的高表面密度的尘埃云，但也使高金属丰度星系的连续体变红。
We derive a UV-optical stellar dust attenuation curve of galaxies at z = 1.4–2.6 as a function of gas-phase metallicity. We use a sample of 218 star-forming galaxies, excluding those with very young or heavily obscured star formation, from the MOSFIRE Deep Evolution Field survey with Hα, Hβ, and [N ii]λ 6585 spectroscopic measurements. We constrain the shape of the attenuation curve by comparing the average flux densities of galaxies sorted into bins of dust obscuration using Balmer decrements, i.e., Hα-to-Hβ luminosities. The average attenuation curve for the high-metallicity sample ( , corresponding to ) has a shallow slope, identical to that of the Calzetti local starburst curve, and a significant UV 2175 Å extinction bump that is ∼0.5× the strength of the Milky Way bump. On the other hand, the average attenuation curve of the low-metallicity sample ( ) has a steeper slope similar to that of the SMC curve, only consistent with the Calzetti slope at the 3σ level. The UV bump is not detected in the low-metallicity curve, indicating the relative lack of the small dust grains causing the bump at low metallicities. Furthermore, we find that on average the nebular reddening (E(B − V)) is a factor of 2 times larger than that of the stellar continuum for galaxies with low metallicities, while the nebular and stellar reddening are similar for galaxies with higher metallicities. The latter is likely due to a high surface density of dusty clouds embedding the star-forming regions but also reddening the continuum in the high-metallicity galaxies.