如果两个初始未结合的物体之间的近距离相遇以引力波（GW）的形式释放出足够的能量，则可能导致双星系统。我们解决的情况下，这种遭遇发生在合并椭圆星系。有证据表明，椭圆星系中可能存在中等质量的黑洞。因此，这些系统可能是引力波源的滋生地，对应于将致密物体吸入大质量黑洞的动力学，大密度和它们包含的致密残余物的数量。我们表明，这一过程是有效的中等质量黑洞（IMBHs）的质量范围从M $\in (10^3,10^5)$ M $_{\odot}$，并导致形成中等质量比inspirals（IMRIs）。我们考虑一组IMBH和质量为$m_2 \in (10,10^3)$ M $_{\odot}$的较小黑洞来估计IMRI形成率。我们发现率范围在10 $^{-8}$年$^{-1}$，和10 $^{-5}$年$^{-1}$，和IMRI形成率每共动体积合并星系作为一个函数的红移。这些IMRI形成时发出的引力辐射的峰值频率在LISA和天琴等星载探测器的探测波段内;考虑到这些探测器的可观测体积，IMRI每年的探测总量是可观的。
英文摘要：
Close encounters between two initially unbound objects can result in a binary system if enough energy is released as gravitational waves (GWs). We address the scenario in which such encounters occur in merging elliptical galaxies. There is evidence that elliptical galaxies can harbor intermediate-mass black holes. Therefore, these systems are potentially the breeding grounds of sources of gravitational waves corresponding to inspiraling compact objects onto a massive black hole due to the dynamics, the large densities, and the number of compact remnants they contain. We show that this process is efficient for intermediate-mass black holes (IMBHs) with masses ranging from M $\in (10^3,10^5)$ M$_{\odot}$ and results in the formation of intermediate mass-ratio inspirals (IMRIs). We consider a set of IMBHs and smaller black holes with masses $m_2 \in (10,10^3)$ M$_{\odot}$ to estimate the IMRI formation rate. We find rates ranging between 10$^{-8}$ yr$^{-1}$, and 10$^{-5}$ yr$^{-1}$, and the IMRI formation rate per comoving volume in merging galaxies as a function of the redshift. The peak frequencies of the gravitational radiation emitted when these IMRIs are formed are within the detection band of space-borne detectors such as LISA and TianQin; taking into account the observable volume of these detectors, the total amount of IMRI detections per year is significant.
Formation of a nuclear star cluster through the inspiral of globular clusters: A case study of the dwarf elliptical galaxy UGC 7346
Institute of Space Technology（太空技术研究所）；National Centre of GIS and Space Applications（国家地理空间与空间应用中心）；New York University Abu Dhabi（阿布扎比纽约大学）；Center for Astrophysics and Space Science（天体物理学与空间科学中心）；Vanderbilt University（范德堡大学）；Fisk University（菲斯克大学）；Nicolaus Copernicus Astronomical Centre, Polish Academy of Sciences（波兰科学院尼古拉·哥白尼天文学中心）；Main Astronomical Observatory, National Academy of Sciences of Ukraine（乌克兰国家科学院主天文台）
A new population of recently quenched elliptical galaxies in the SDSS
We use the Sloan Digital Sky Survey to investigate the properties of massive elliptical galaxies in the local Universe (z \leq 0.08) that have unusually blue optical colors. Through careful inspection, we distinguish elliptical from non-elliptical morphologies among a large sample of similarly blue galaxies with high central light concentrations (c_r \geq 2.6). These blue ellipticals comprise 3.7 per cent of all c_r \geq 2.6 galaxies with stellar masses between 10^10 and 10^11 h^{-2} { \rm M}_{ \sun }. Using published fiber spectra diagnostics, we identify a unique subset of 172 non-star-formi…
