Title: Gravitational Recoil and Suppression of Super Massive Black Hole Seeds in the Early Universe Show Chinese title

Title: 引力反冲和早期宇宙中超大质量黑洞种子的抑制

Abstract: We investigate the impact of gravitational-wave (GW) recoil on the growth of supermassive black holes (SMBHs) in the early Universe. Forming ~10^9 Msun SMBHs by z ~ 6 is challenging and may require hierarchical mergers of smaller seed black holes. We extend a semi-analytic seed model (Sassano et al. 2021) by explicitly incorporating GW recoil physics. Our model includes: (1) recoil velocity formulae calibrated to numerical relativity for spinning, unequal-mass BH binaries (Campanelli et al. 2007; Lousto et al. 2012); (2) assignment of spin magnitudes and orientations based on seed type (Pop III remnant, stellar cluster, or direct-collapse); and (3) a retention probability scheme comparing the recoil speed to the host halo escape velocity. We find that including GW recoil reduces final SMBH masses by ~20-30% by z = 6 and creates a population of off-nuclear ("wandering") BHs amounting to a few percent of the total. Observable consequences include spatial offsets ~0.1 arcsec and line-of-sight velocity shifts ~10^2-10^3 km/s in a few percent of high-z quasars. All code is publicly available at https://github.com/SMALLSCALEDEV/Black-hole-Recoil-Effects Show Chinese abstract

Abstract: 我们研究引力波（GW）反冲对早期宇宙中超大质量黑洞（SMBH）增长的影响。 在红移 z ~ 6 之前形成 ~10^9 Msun 的 SMBH 是具有挑战性的，可能需要较小种子黑洞的分层合并。 我们通过明确引入 GW 反冲物理来扩展一种半解析种子模型（Sassano 等，2021）。 我们的模型包括：（1）根据数值相对论校准的旋转、非等质量黑洞双星的反冲速度公式（Campanelli 等，2007；Lousto 等，2012）；（2）根据种子类型（第一代恒星遗迹、恒星团或直接塌缩）分配自旋大小和方向；以及（3）一种保留概率方案，将反冲速度与宿主晕逃逸速度进行比较。 我们发现，包括 GW 反冲会使 z = 6 时最终 SMBH 质量减少约 20-30%，并产生少量（占总数的几个百分比）偏离核区（“游荡”）的 BH。 可观测后果包括在少数百分之几的高红移类星体中出现空间偏移 ~0.1 角秒和视线速度位移 ~10^2-10^3 km/s。 所有代码均可在 https://github.com/SMALLSCALEDEV/Black-hole-Recoil-Effects 公开获取。