arXivDaily arXiv每日学术速递 周一至周五更新
北美退伍军人节(Veterans Day),12 日无更新
arXiv 2202.05102astro-ph.GAastro-ph.IM
收藏

沙尘暴观测衰减的贝叶斯总体模型

A Bayesian Population Model for the Observed Dust Attenuation in Galaxies

Gautam Nagaraj, John C. Forbes, Joel Leja, Daniel Foreman-Mackey, Christopher C. Hayward

摘要:

尘埃在确定星系观测到的光谱能量分布(SED)中起着关键作用。然而,我们对尘埃衰减的理解是有限的,我们的观测遭受的尘埃金属丰度年龄简并在SED拟合(单星系),大的个体方差(合奏测量),并在适当处理不确定性(统计考虑)的困难。在这项研究中,我们创建了一个人口贝叶斯模型,严格考虑相关变量和非高斯误差分布,并证明了一个简单的贝叶斯模型的改进。我们采用了灵活的5-D线性插值模型的参数,控制尘埃衰减曲线作为恒星质量,恒星形成率(SFR),金属丰度,红移和倾角的函数。我们的设置使我们能够同时确定尘埃衰减和这些星系属性之间的复杂关系。使用Prospector拟合近30,000个3D-HST星系,我们发现衰减斜率($n$)随光学深度($τ$)的增加而增加,尽管比以前的研究要小。$τ$随着SFR的增加而强烈增加,尽管当$\log~{\rm SFR}\lesssim 0$,$τ$在很大的恒星质量范围内保持大致恒定。边缘星系的$τ$往往比正面星系的大,但仅限于$\log~M_*\gtrsim 10$,反映了低质量星系缺乏三轴性。尘埃衰减的红移演化对于低质量、低SFR的星系是最强的,在高红移处具有更高的光学深度但更平坦的曲线。最后,$n$与恒星质量有着复杂的关系,突出了星尘几何形状的复杂性。我们已经公开发布了软件(https://github.com/Astropianist/DustE),供用户访问我们的人口模型。

英文摘要:

Dust plays a pivotal role in determining the observed spectral energy distribution (SED) of galaxies. Yet our understanding of dust attenuation is limited and our observations suffer from the dust-metallicity-age degeneracy in SED fitting (single galaxies), large individual variances (ensemble measurements), and the difficulty in properly dealing with uncertainties (statistical considerations). In this study, we create a population Bayesian model to rigorously account for correlated variables and non-Gaussian error distributions and demonstrate the improvement over a simple Bayesian model. We employ a flexible 5-D linear interpolation model for the parameters that control dust attenuation curves as a function of stellar mass, star formation rate (SFR), metallicity, redshift, and inclination. Our setup allows us to determine the complex relationships between dust attenuation and these galaxy properties simultaneously. Using Prospector fits of nearly 30,000 3D-HST galaxies, we find that the attenuation slope ($n$) flattens with increasing optical depth ($τ$), though less so than in previous studies. $τ$ increases strongly with SFR, though when $\log~{\rm SFR}\lesssim 0$, $τ$ remains roughly constant over a wide range of stellar masses. Edge-on galaxies tend to have larger $τ$ than face-on galaxies, but only for $\log~M_*\gtrsim 10$, reflecting the lack of triaxiality for low-mass galaxies. Redshift evolution of dust attenuation is strongest for low-mass, low-SFR galaxies, with higher optical depths but flatter curves at high redshift. Finally, $n$ has a complex relationship with stellar mass, highlighting the intricacies of the star-dust geometry. We have publicly released software (https://github.com/Astropianist/DustE) for users to access our population model.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑