来自 CHIME/FRB 目录 2 中微引力透镜特征的证据：中等质量黑洞

本文利用快速射电暴（FRB）的微引力透镜效应，在 CHIME/FRB 目录 2 中搜寻中等质量黑洞（IMBH）。研究识别出两个疑似透镜特征，推断其透镜质量范围暗示了中等质量黑洞的存在，并探讨了其作为原初黑洞（PBH）的可能性及其对暗物质丰度的贡献。

arXiv:2605.19653v3 Announce Type: replace Abstract: Intermediate-mass black holes (IMBHs) are the missing link in the cosmic hierarchy of black holes, bridging the gap between stellar-mass black holes and supermassive ones. They also serve as unique laboratories for testing strong-field gravity and are prime targets for future multi-messenger observations. However, IMBHs are a population that has remained notoriously difficult to detect. The microlensing effect of fast radio bursts (FRBs) can serve as a clean and powerful method to probe IMBHs. In this work, we develop a pipeline to search for microlensed FRBs based on their dynamic spectra and apply it to the CHIME/FRB Catalog 2. Two microlensing signatures have been identified in two separate sources, i.e. FRB~20190131D and FRB~20211115A. The inferred lens masses for these two signatures are $\sim[280-467]~M_{\odot}$ and $\sim[539-609]~M_{\odot}$, respectively. Here we interpret them as evidence for IMBHs. If there are no intervening structures-such as galaxies or clusters-along the line of sights for these two sources, the two identified IMBHs might be isolated and of primordial origins. In that case, we obtain primordial black holes (PBHs) within these two mass ranges would constitute $\sim4\%$ of dark matter. Moreover, if these two candidates are not genuine lensing signatures, the abundance