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arXiv 0904.2355astro-ph.CO
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第一颗超新星对邻近暗物质晕的反馈效应

Feedback Effects of First Supernovae on the Neighboring Dark Matter Halos

Masaru Sakuma, Hajime Susa

摘要:

$Λ$ CDM宇宙中的第一代恒星被认为是在黑暗的晕中形成的,总质量在$z \sim 20-50$的$\sim 10^{5}-10^{7}M_sun$范围内。这些恒星被认为是非常巨大的,在某些情况下,它们会以第一颗超新星(SNe)的形式结束生命。我们探讨了低质量暗晕(< 10^{7} M_sun)中恒星形成是否被邻近恒星形成晕的SN反馈触发或抑制的问题。我们主要考虑了SN激波的两个作用:一是从晕中抽空气体组分,二是由于激波加热增强电离度而促进H_2的生成。综合上述效应,我们发现当邻近的暗物质晕(M < 10^{7} Msun)靠近SN中心时,由于气体排空效应,其恒星形成活动基本上受到抑制。气体被吹走的临界距离落在$\sim 0.3-1.5$ kpc的范围内,这取决于SN能量和晕质量。此外,我们发现在参数空间中,暗晕中的恒星形成活动被邻近的SN诱导或促进的窗口非常小。

英文摘要:

The first-generation stars in the $Λ$CDM universe are considered to have formed in dark halos with total masses in the range $\sim 10^{5}-10^{7}M_sun$ at $z \sim 20-50$. These stars expected to be very massive and in some cases they end their lives as the first supernovae (SNe). We explore the problem of whether star formation in low mass dark halos (< 10^{7} M_sun) was triggered or suppressed by the SN feedback from neighboring star-forming halos. We take into consideration mainly two effects by the SN shock: one is the evacuation of gas components from the halos and the other is the promotion of H_2 formation because of the enhanced ionization degree by shock heating. Combining above effects, we find that the star formation activities in the neighboring dark matter halos (M < 10^{7} M_sun) are basically suppressed in case they are located close to the SN center, because of the gas evacuation effect. The critical distance within which the gas is blown away falls within the range $\sim 0.3-1.5$kpc depending on the SN energy and the halo mass. In addition, we find there is very little window in the parameter space where star formation activities in dark halos are induced or promoted by neighboring SN.

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