arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2201.05467astro-ph.GA
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通过星系SED拟合确定尘埃衰减曲线的系统偏差

Systematic biases in determining dust attenuation curves through galaxy SED fitting

Jianbo Qin, Xian Zhong Zheng, Min Fang, Zhizheng Pan, Stijn Wuyts, Yong Shi, Yingjie Peng, Valentino Gonzalez, Fuyan Bian, Jia-Sheng Huang, Qiu-Sheng Gu, Wenhao… 展开作者

Jianbo Qin, Xian Zhong Zheng, Min Fang, Zhizheng Pan, Stijn Wuyts, Yong Shi, Yingjie Peng, Valentino Gonzalez, Fuyan Bian, Jia-Sheng Huang, Qiu-Sheng Gu, Wenhao Liu, Qinghua Tan, Dong Dong Shi, Jian Ren, Yuheng Zhang, Man Qiao, Run Wen, Shuang Liu

摘要:

虽然尘埃衰减曲线($δ$)的斜率被发现与有效尘埃衰减($A_V$)通过光谱能量分布(SED)拟合获得相关,它仍然是未知的拟合退化如何塑造这种关系。我们研究的简并效应拟合SED的本地恒星形成星系(SFGs)的样本从银河系和质量大会调查,结合模拟星系SED已知的衰减参数。一个精心设计的下降的星爆恒星形成历史,生成模型SED模板与内在的UV斜率($β_0$)跨越一个合理的范围。我们的样本SFG的最佳拟合$β_0$显示了广泛的覆盖范围,显着不同的有限范围的$β_0<-2.2$的恒星形成的恒星爆发。我们的研究结果表明,强退化$β_0$,$δ$,和$A_V$在SED拟合诱导系统偏差,导致一个错误的$A_V$ - $δ$相关。我们的模拟测试表明,这种关系可以很好地再现,即使当一个平坦的$A_V$ - $δ$关系被用来建立输入模型星系SED。最佳拟合$δ$的变化主要由拟合误差决定。我们发现,假设恒星形成的恒星暴在SED拟合将导致一个陡峭的衰减曲线,较小的简并误差,和更强的$A_V$ - $δ$关系。我们的研究结果证实,通过SED拟合获得的$A_V$- $δ$关系可能是由$β_0$、$δ$和$A_V$之间的拟合简并引起的系统偏倚驱动的。

英文摘要:

While the slope of the dust attenuation curve ($δ$) 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 ($β_0$) spanning over a reasonably wide range. The best-fitting $β_0$ for our sample SFGs shows a wide coverage, dramatically differing from the limited range of $β_0<-2.2$ for a starburst of constant star formation. Our results show that strong degeneracies between $β_0$, $δ$, and $A_V$ in the SED fitting induce systematic biases leading to a false $A_V$--$δ$ correlation. Our simulation tests reveal that this relationship can be well reproduced even when a flat $A_V$--$δ$ relation is taken to build the input model galaxy SEDs. The variations in best-fitting $δ$ 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 $A_V$--$δ$ relation. Our findings confirm that the $A_V$--$δ$ relation obtained through SED fitting is likely driven by the systematic biases induced by the fitting degeneracies between $β_0$, $δ$, and $A_V$.

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