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arXiv 2103.06887astro-ph.GAastro-ph.CO
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尘埃的后期宇宙演化:解决难题

Late-time cosmic evolution of dust: solving the puzzle

A. Ferrara, C. Peroux

摘要:

尘埃是星系的基本成分,决定了星际介质的物理和化学条件。几个互补的观测证据表明,宇宙尘埃的质量密度显着下降,从红移$z=1$到$z=0$。显然,在宇宙演化过程中,尘埃的毁灭速度必须比它的形成速度更快,这是第一次。通过考虑尘埃的产生/破坏过程,我们发现,如果尘埃主要是由星暴(基准情况下占49%)和星系内的超新星冲击(占42%)破坏的话,那么尘埃的下降可以得到解释。我们的研究结果进一步表明,平均而言,每颗超新星只破坏$M_{d,sn} =0.45\, M_\odot$的尘埃,即$5-10$倍小于通常假设,与硬上限$M_{d,sn} < {3.0} M_\odot$设置的可用金属预算和最大晶粒生长。效率较低的原因可能是超新星爆发前的风壳有效地屏蔽了尘埃对冲击波的影响。

英文摘要:

Dust is an essential ingredient of galaxies, determining the physical and chemical conditions in the interstellar medium. Several complementary observational evidences indicate that the cosmic dust mass density significantly drops from redshift $z=1$ to $z=0$. Clearly, and for the first time during cosmic evolution, dust must be destroyed more rapidly than it is formed. By considering the dust production/destruction processes acting in this cosmic time lapse, we find that the drop can be explained if dust is mainly destroyed by astration (49\% contribution in the fiducial case) and supernova shocks within galaxies (42\%). Our results further imply that on average each supernova destroys only $M_{d,sn} =0.45\, M_\odot$ of dust, i.e. $5-10$ times less than usually assumed, with a hard upper limit of $M_{d,sn} < {3.0} M_\odot$ set by the available metal budget and maximal grain growth. The lower efficiency might be explained by effective shielding of dust against shock processing in pre-supernova wind shells.

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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