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arXiv 1507.00728astro-ph.GA
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尘埃星系及其尘埃分布与衰减公式之间的简并性

Dusty galaxies and the degeneracy between their dust distributions and the attenuation formula

Kyle Penner, Mark Dickinson, Benjamin Weiner, Hanae Inami, Jeyhan Kartaltepe, Janine Pforr, Hooshang Nayyeri, Susan Kassin, Casey Papovich, Alexandra Pope

摘要:

星系中尘埃颗粒的空间分布是否像恒星的空间分布一样具有典型的形式?我们调查的分布是否类似于均匀的前景屏幕,通常假设的高红移星系社区。我们使用静止帧红外,紫外和H $α$线光度的尘埃贫和尘埃星系在z ~ 0和z ~ 1比较测量的H $α$逃逸分数与预测的Calzetti衰减公式。的预测,紫外逃逸分数的基础上,高估了测量的H $α$逃逸分数的所有样品。对贫尘z ~ 0星系的这一结果的解释是,有电离恒星的区域比有非电离紫外辐射恒星的区域有更多的尘埃。这些星系的尘埃分布是不均匀的。尘埃星系在两个红移上的高估解释还不太清楚。如果衰减公式不适用于这些星系,也许这些分歧是非物理的;也许这些星系中的尘埃分布是均匀的。如果衰减公式确实适用,那么尘埃星系的尘埃分布是不均匀的;这种分布比缺乏尘埃的星系更均匀。z ~ 1尘埃星系在给定UV逃逸分数下的H $α$逃逸分数范围很广,如果是真的,则表明尘埃形态多样,屏假设不可信。

英文摘要:

Do spatial distributions of dust grains in galaxies have typical forms, as do spatial distributions of stars? We investigate whether or not the distributions resemble uniform foreground screens, as commonly assumed by the high-redshift galaxy community. We use rest-frame infrared, ultraviolet, and H$α$ line luminosities of dust-poor and dusty galaxies at z ~ 0 and z ~ 1 to compare measured H$α$ escape fractions with those predicted by the Calzetti attenuation formula. The predictions, based on UV escape fractions, overestimate the measured H$α$ escape fractions for all samples. The interpretation of this result for dust-poor z ~ 0 galaxies is that regions with ionizing stars have more dust than regions with nonionizing UV-emitting stars. Dust distributions for these galaxies are nonuniform. The interpretation of the overestimates for dusty galaxies at both redshifts is less clear. If the attenuation formula is inapplicable to these galaxies, perhaps the disagreements are unphysical; perhaps dust distributions in these galaxies are uniform. If the attenuation formula does apply, then dusty galaxies have nonuniform dust distributions; the distributions are more uniform than they are in dust-poor galaxies. A broad range of H$α$ escape fractions at a given UV escape fraction for z ~ 1 dusty galaxies, if real, indicates diverse dust morphologies and the implausibility of the screen assumption.

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。

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