Simulating kilonovae in the ΛCDM universe
Simulating kilonovae in the ΛCDM universe
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模拟ÎCDM 宇宙中的千新星
DOI：
10.1093/mnras/staa1989
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发表时间：
2020
期刊：
影响因子：
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通讯作者：
J. Pan
中科院分区：
文献类型：
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作者：
Z. Jiang;J. Wang;张奉辉;L. Li;L. Wang;R. Li;L. Gao;韩占文;J. Pan
千新星是在中子星 - 中子星并合或中子星 - 黑洞并合之后产生的光学闪光。在这项工作中，我们利用千禧模拟，结合半解析星系形成模型GABE（含双星演化的星系组装模型）来探究千新星的宇宙事件率，以及它们在宇宙学背景下宿主星系的性质。我们发现超新星反冲速度为\(|V_{\rm kick}=0\ {\rm km}\ {\rm s}^{-1}|\)的模型与观测结果最为吻合，满足理论模型中对低反冲速度双星系统的偏好。当\(|V_{\rm kick}=0\ {\rm km}\ {\rm s}^{-1}|\)时，在\(z = 0\)处中子星 - 中子星并合（NNMs）和中子星 - 黑洞并合（NBMs）的宇宙事件率分别为\(283\)和\(|91\ {\rm Gpc}^{-3}\ {\rm yr}^{-1}|\)，与LVC GWTC - 1的限制大致相符。对于银河系质量的星系，我们预测中子星 - 中子星并合率为\(|25.7^{+59.6}_{-7.1}\ {\rm Myr}^{-1}|\)，这也与银河系中双中子星的观测性质高度吻合。考虑到银河系质量星系历史上所有的千新星，我们发现中子星 - 中子星并合/中子星 - 黑洞并合事件中平均的\(r\) - 过程元素产量（\(A > 79\)）应为\(|0.01\ {\rm M}_\odot|\)才能与观测结果一致。我们得出结论，GW170817的宿主星系NGC 4993是中子星 - 中子星并合的一个典型宿主星系。然而，一般来说，中子星 - 中子星并合和中子星 - 黑洞并合往往发生在年轻、蓝色、正在形成恒星的晚型星系中，其恒星质量和气体金属丰度分布分别在\(|M_{\rm *}=10^{10.65}\ {\rm M}_\odot|\)和\(12 + \log (O/H) = 8.72 - 8.85\)处达到峰值。通过在宇宙学背景下探究千新星与其宿主星系之间的联系，当未来有更多事件时，有望更好地约束模型。
Kilonovae are optical flashes produced in the aftermath of neutron star–neutron star mergers or neutron star–black hole mergers. In this work, we use the Millennium Simulation, combined with semi-analytic galaxy formation model GABE (Galaxy Assembly with Binary Evolution) to explore the cosmic event rate of kilonovae, and the properties of their host galaxies in a cosmological context. We find that model with supernova kick velocity of |$V_{\rm kick}=0\, \, {\rm km}\, \, {\rm s}^{-1}$| fits the observation best, satisfying the preference for low kick velocity binary system in theoretical models. With |$V_{\rm kick}=0\, \, {\rm km}\, \, {\rm s}^{-1}$|, the cosmic event rate of NNMs and NBMs at z = 0 are 283 and |$91\, \, {\rm Gpc}^{-3}\, \, {\rm yr}^{-1}$|, respectively, marginally consistent with the constraint from LVC GWTC-1. For Milky Way-mass galaxies, we predict the NNM rate is |$25.7^{+59.6}_{-7.1}\, {\rm Myr}^{-1}$|, which is also in good agreement with the observed properties of binary neutron stars in the Milky Way. Taking all the kilonovae into account in the history of Milky Way-mass galaxies, we find that the averaged r-process elements yield (A > 79) in an NNM/NBM event should be |$0.01\, {\rm M}_\odot$| to be consistent with observation. We conclude that NGC 4993, the host galaxy of GW170817, is a typical host galaxy for NNMs. However, generally, NNMs and NBMs tend to reside in young, blue, star-forming, late-type galaxies, with stellar mass, and gaseous metallicity distribution peaking at |$M_{\rm *}=10^{10.65}\, {\rm M}_\odot$| and 12 + log (O/H) = 8.72 − 8.85, respectively. By exploring the connection between kilonovae and their host galaxies in the cosmological background, it is promising to constrain model better when we have more events in the forthcoming future.