论文标题

h的大规模模拟和他的电源和加热是由恒星和更充满活力的来源驱动的

Large scale simulations of H and He reionization and heating driven by stars and more energetic sources

论文作者

Eide, Marius B., Ciardi, Benedetta, Graziani, Luca, Busch, Philipp, Feng, Yu, Di Matteo, Tiziana

论文摘要

我们介绍了宇宙恢复和从$ z = 18 $重新加热到$ z = 5 $的模拟,调查了星星(发射软紫外线)的作用,核黑洞(BHS,带有幂律光谱),X射线二进制文件,X-ray Binaries(XRB,硬X射线X射线主导型光谱),以及超级互联网介绍的介绍互联网,并散发出层次介绍的互联网, (ISM,具有软X射线光谱)。我们后处理具有多频电离辐射转移的巨大黑色II(MBII)。源属性直接源自MBII的物理环境,我们唯一的真正免费参数是电离逃生分数$ f _ {\ rm ESC} $。我们发现,在此处探索的模型中,具有逃生部分的模型随着红移产量的降低而降低的结果最与观测值(例如中性氢分位和汤姆森散射光学深度)最一致。恒星是氢气离子的主要驱动力,因此是恒星层间培养基(IGM)的热史的驱动力。我们获得了$ \ langle x _ {\ rm hii} \ rangle = 0.99998 $ at $ z = 6 $,所有源类型的温度平均温度$ \ langle t \ rangle \ rangle \ sim 20,000〜 {\ rm k} $。 BHS在氢气回离时很少见,但相反,它们是唯一可以完全电离氦气的来源,将局部温度增加$ \ sim 10^4〜 {\ rm k} $。中性和降低电离氢的热和电离状态与不同的源组合,ISM和(较小程度上)XRBS显着不同,从而确定了从中性氢的吸收到21 cm信号的发射到21 cm信号的发射的过渡。

We present simulations of cosmic reionization and reheating from $z=18$ to $z=5$, investigating the role of stars (emitting soft UV-photons), nuclear black holes (BHs, with power-law spectra), X-ray binaries (XRBs, with hard X-ray dominated spectra), and the supernova-associated thermal bremsstrahlung of the diffuse interstellar medium (ISM, with soft X-ray spectra). We post-process the hydrodynamical simulation Massive-Black II (MBII) with multifrequency ionizing radiative transfer. The source properties are directly derived from the physical environment of MBII, and our only real free parameter is the ionizing escape fraction $f_{\rm esc}$. We find that, among the models explored here, the one with an escape fraction that decreases with decreasing redshift yields results most in line with observations, such as of the neutral hydrogen fraction and the Thomson scattering optical depth. Stars are the main driver of hydrogen reionization and consequently of the thermal history of the intergalactic medium (IGM). We obtain $\langle x_{\rm HII} \rangle = 0.99998$ at $z=6$ for all source types, with volume averaged temperatures $\langle T \rangle \sim 20,000~{\rm K}$. BHs are rare and negligible to hydrogen reionization, but conversely they are the only sources which can fully ionize helium, increasing local temperatures by $\sim 10^4~{\rm K}$. The thermal and ionization state of the neutral and lowly ionized hydrogen differs significantly with different source combinations, with ISM and (to a lesser extent) XRBs, playing a significant role and, as a consequence, determining the transition from absorption to emission of the 21 cm signal from neutral hydrogen.

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