Systematic biases in determining dust attenuation curves through galaxy SED fitting
| Autor: | Qin, Jianbo, Zheng, Xian Zhong, Fang, Min, Pan, Zhizheng, Wuyts, Stijn, Shi, Yong, Peng, Yingjie, Gonzalez, Valentino, Bian, Fuyan, Huang, Jia-Sheng, Gu, Qiu-Sheng, Liu, Wenhao, Tan, Qinghua, Shi, Dong Dong, Ren, Jian, Zhang, Yuheng, Qiao, Man, Wen, Run, Liu, Shuang |
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| Rok vydání: | 2022 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1093/mnras/stac132 |
| Popis: | While the slope of the dust attenuation curve ($\delta$) is found to correlate with effective dust attenuation ($A_V$) as obtained through spectral energy distribution (SED) fitting, it remains unknown how the fitting degeneracies shape this relation. We examine the degeneracy effects by fitting SEDs of a sample of local star-forming galaxies (SFGs) selected from the Galaxy And Mass Assembly survey, in conjunction with mock galaxy SEDs of known attenuation parameters. A well-designed declining starburst star formation history is adopted to generate model SED templates with intrinsic UV slope ($\beta_0$) spanning over a reasonably wide range. The best-fitting $\beta_0$ for our sample SFGs shows a wide coverage, dramatically differing from the limited range of $\beta_0<-2.2$ for a starburst of constant star formation. Our results show that strong degeneracies between $\beta_0$, $\delta$, and $A_V$ in the SED fitting induce systematic biases leading to a false $A_V$--$\delta$ correlation. Our simulation tests reveal that this relationship can be well reproduced even when a flat $A_V$--$\delta$ relation is taken to build the input model galaxy SEDs. The variations in best-fitting $\delta$ are dominated by the fitting errors. We show that assuming a starburst with constant star formation in SED fitting will result in a steeper attenuation curve, smaller degeneracy errors, and a stronger $A_V$--$\delta$ relation. Our findings confirm that the $A_V$--$\delta$ relation obtained through SED fitting is likely driven by the systematic biases induced by the fitting degeneracies between $\beta_0$, $\delta$, and $A_V$. Comment: 21 pages, 13 figures, accepted for publication in the MNRAS, Comments welcome! |
| Databáze: | arXiv |
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