The log-normal shape of the mass function for metal-poor halo globular clusters is proposed to result from an initial M^{-2} power law modified rapidly by evaporation, collisions with clouds, and mutual cluster interactions in the dense environment of a redshift z~5-15 disk galaxy. Galaxy interactions subsequently spray these clusters into the galaxy group environment, where they fall into other growing galaxies and populate their halos. Clusters forming later in z~2-5 galaxies, and those formed during major mergers, produce metal-rich globulars. Monte Carlo models of evolving cluster populations demonstrate the early formation of a log-normal mass function for typical conditions in high-redshift galaxies.
How stars in globular clusters reveal the depletion of the Spite plateau of lithium
我总结了15年来对球状星团中恒星表面丰度的研究结果。球状星团恒星为塑造斯皮特高原及以外恒星表面丰度的物理过程提供了独特的视角,因为人们可以研究处于不同进化阶段且出生时成分相同的恒星。主要结果是发现了重元素(Mg、Ca、Ti、Cr、Fe、Ba)表面丰度的观测趋势,其范围从~0.1 dex(M4 at [Fe/H]=-1.1)到~0.3 dex(M30 at [Fe/H]=-2.3),关闭星和次巨星的丰度通常低于巨星。任何试图通过恒星物理学解决宇宙学锂差异的模型都必须同时描述矮星和巨星之间的这些系统性重元素趋势。通过一些额外的混合调节的原子扩散模型确实可以解释观察到的丰度趋势,并对锂的耗尽进行定量预测。推测的Spite-plateau恒星的诞生云锂丰度高出约0.3 dex,留下一个小的(约0.15 dex)名义偏移的原始值。
Stellar Population Properties of Ultracompact Dwarfs in M87: a Mass-metallicity Correlation Connecting Low-metallicity Globular Clusters and Compact Ellipticals
Milky Way Globular Clusters: Nurseries for Dynamically-Formed Binary Black Holes
Sapienza, Università di Roma(罗马大学);Tor Vergata, Università di Roma(罗马托尔维加塔大学);INAF/Osservatorio Astronomico di Roma(意大利国家天体物理研究所罗马天文台);INFN, Sezione di Roma I(意大利国家核物理研究所罗马第一分部);Johns Hopkins University(约翰斯·霍普金斯大学);Max-Planck-Institut für Astronomie(马克斯·普朗克天文学研究所)
Massive star clusters detected by JWST as natural birth places to form intermediate-mass black holes
Sapienza Università di Roma(罗马第一大学);Nicolaus Copernicus Astronomical Centre, Polish Academy of Sciences(波兰科学院尼古拉·哥白尼天文学中心);Astronomisches Rechen-Institut, Zentrum für Astronomie, University of Heidelberg(海德堡大学天体物理计算研究所);Department of Physics, New York University Abu Dhabi(阿布扎比纽约大学物理系);Center for Astrophysics and Space Science (CASS), New York University Abu Dhabi(阿布扎比纽约大学天体物理学与空间科学中心);Hamburg Observatory, Hamburg University(汉堡大学汉堡天文台);Departamento de Astronomía, Universidad de Chile(智利大学天文学系);Physics Department, College of Science, United Arab Emirates University(阿联酋大学理学院物理系)