We investigate signatures of population III (PopIII) stars in the metal-enriched environment of GRBs originating from population II-I (PopII/I) stars by using abundance ratios derived from numerical simulations that follow stellar evolution and chemical enrichment. We find that at $z>10$ more than $10%$ of PopII/I GRBs explode in a medium previously enriched by PopIII stars (we refer to them as GRBII$\rightarrow$III). Although the formation of GRBII$\rightarrow$III is more frequent than that of pristine PopIII GRBs (GRBIIIs), we find that the expected GRBII$\rightarrow$III observed rate is comparable to that of GRBIIIs, due to the usually larger luminosities of these latter. GRBII$\rightarrow$III events take place preferentially in small proto-galaxies with stellar masses $\rm M_\star \sim 10^{4.5} - 10^7\,\rm M_\odot$, star formation rates $\rm SFR \sim 10^{-3}-10^{-1}\,\rm M_\odot/yr$ and metallicities $Z \sim 10^{-4}-10^{-2}\,\rm Z_\odot$. On the other hand, galaxies with $Z < 10^{-2.8}\,\rm Z_\odot$ are dominated by metal enrichment from PopIII stars and should preferentially host GRBII$\rightarrow$III. Hence, measured GRB metal content below this limit could represent a strong evidence of enrichment by pristine stellar populations. We discuss how to discriminate PopIII metal enrichment on the basis of various abundance ratios observable in the spectra of GRBs' afterglows. By employing such analysis, we conclude that the currently known candidates at redshift $z\simeq 6$ -- i.e. GRB 050904 \cite[][]{2006Natur.440..184K} and GRB 130606A \cite[][]{2013arXiv1312.5631C} -- are likely not originated in environments pre-enriched by PopIII stars.
利用数值N体/流体动力学模拟方法，研究了在高红移的PopII GRBs（GRBIs）观测中，从不同初始质量函数（IMF）、产额和寿命的恒星星族中探测和区分PopIII星富集特征的可能性。PopIII和PopII的恒星形成制度，同时采用头重脚轻和Salpeter-like IMF的原始PopIII恒星形成。我们发现，部分GRBIIs托管在介质中以前丰富的PopIII星（PopIII为主）是模型独立的。典型的丰度比，如[Si/O] vs [C/O]和[Fe/C] vs [Si/C]，可以帮助从大质量和中等质量的PopIII恒星中分离富集，而低质量的第一颗恒星则与常规的PopII世代退化。拥有PopIII主导的GRBII的星系的性质对第一颗恒星质量的特定假设并不十分敏感。
The Pristine HeII Emitter near GN-z11: Constraining the Mass Distribution of the First Stars
Università degli Studi di Firenze（佛罗伦萨大学）；INAF/Osservatorio Astrofisico di Arcetri（意大利国家天体物理研究所阿切尔奇天文台）；Kavli Institute for Cosmology, University of Cambridge（剑桥大学卡弗里宇宙学研究所）；Cavendish Laboratory, University of Cambridge（剑桥大学卡文迪许实验室）；Department of Physics and Astronomy, University College London（伦敦大学学院物理与天文系）；Cosmic Dawn Center (DAWN)（宇宙黎明中心）；Niels Bohr Institute, University of Copenhagen（哥本哈根大学尼尔斯·玻尔研究所）；Scuola Normale Superiore（比萨高等师范学院）；Max-Planck-Institut für extraterrestrische Physik（马克斯·普朗克地外物理研究所）
GLIMPSE: An ultra-faint $\simeq$ 10$^{5}$ $M_{\odot}$ Pop III Galaxy Candidate and First Constraints on the Pop III UV Luminosity Function at $z\simeq6-7$
Signatures of Exploding Supermassive PopIII Stars at High Redshift in JWST, EUCLID and Roman Space Telescope
Max Planck Institute for Gravitational Physics (Albert Einstein Institute)（马克斯·普朗克引力物理研究所（爱因斯坦研究所））；Institute for Cosmic Ray Research, The University of Tokyo（东京大学宇宙射线研究所）；Center for Gravitational Physics and Quantum Information, Yukawa Institute for Theoretical Physics, Kyoto University（京都大学汤川理论物理中心引力物理与量子信息研究中心）；Frontier Research Institute for Interdisciplinary Sciences, Tohoku University（东北大学前沿交叉科学研究所）；Astronomical Institute, Graduate School of Science, Tohoku University（东北大学理学研究科天文学系）
NEFERTITI: Linking early galaxy formation to the assembly of the Milky Way
INAF/Osservatorio Astrofisico di Arcetri（意大利国家天体物理研究所阿切特里天文台）；Cosmic Dawn Center (DAWN)（宇宙黎明中心）；Niels Bohr Institute, University of Copenhagen（哥本哈根大学尼尔斯玻尔研究所）；Instituto de Astrofísica de Canarias（加那利群岛天体物理研究所）；Universidad de La Laguna（拉古纳大学）
GA-NIFS and JADES: Confirmation of pristine gas near GN-z11
Max-Planck-Institut für extraterrestrische Physik（马克斯·普朗克地外物理研究所）；Kavli Institute for Cosmology, University of Cambridge（剑桥大学卡弗里宇宙学研究所）；Cavendish Laboratory, University of Cambridge（剑桥大学卡文迪许实验室）；Department of Physics and Astronomy, University College London（伦敦大学学院物理与天文系）；Centro de Astrobiología (CAB), CSIC–INTA（西班牙国家航空航天技术研究所/西班牙国家科学研究委员会天体生物学中心）；Waseda Research Institute for Science and Engineering, Faculty of Science and Engineering, Waseda University（早稻田大学理工学部理工学研究科）；AURA for European Space Agency (ESA), ESA Office, Space Telescope Science Institute（空间望远镜科学研究所）；Sorbonne Université, CNRS, UMR 7095, Institut d’Astrophysique de Paris（巴黎天体物理学研究所）；Dipartimento di Fisica e Astronomia, Università degli Studi di Firenze（佛罗伦萨大学物理与天文系）
CRIMSONS: An Online Tool for Modeling Chemical Enrichment with Stochastic IMF Sampling
Alma Mater Studiorum, Università di Bologna（博洛尼亚大学）；INAF, Osservatorio di Astrofisica e Scienza dello Spazio（意大利国家天体物理研究所）；INAF, Osservatorio Astrofisico di Arcetri（阿切特里天文台）；Kapteyn Astronomical Institute, University of Groningen（格罗宁根大学卡普坦天文研究所）；Cosmic Dawn Center (DAWN)（宇宙黎明中心）
JADES: Carbon-enhanced, Nitrogen-normal compact galaxy at z=11.2
University of Cambridge（剑桥大学）；Centre for Astrophysics Research, Department of Physics, Astronomy and Mathematics, University of Hertfordshire（赫特福德大学物理、天文与数学系天体物理学研究中心）；Department of Physics and Astronomy, University College London（伦敦大学学院物理与天文系）；Scuola Normale Superiore（意大利高等师范学院）；Cosmic Dawn Center (DAWN)（宇宙黎明中心）；Niels Bohr Institute, University of Copenhagen（哥本哈根大学尼尔斯·玻尔研究所）；Steward Observatory, University of Arizona（亚利桑那大学斯图尔德天文台）；Centro de Astrobiología (CAB), CSIC–INTA（西班牙国家航空航天技术研究所-西班牙国家研究委员会天体生物学中心）；European Space Agency (ESA), European Space Astronomy Centre (ESAC)（欧洲航天局欧洲空间天文中心）；University of Oxford（牛津大学）；Sorbonne Université, CNRS, UMR 7095, Institut d’Astrophysique de Paris（索邦大学法国国家科学研究中心巴黎天体物理研究所）；European Southern Observatory（欧洲南方天文台）；Center for Astrophysics | Harvard & Smithsonian（哈佛-史密森天体物理中心）；Waseda Research Institute for Science and Engineering, Faculty of Science and Engineering, Waseda University（早稻田大学理工学研究科理工学研究院）；Department of Astronomy and Astrophysics, University of California, Santa Cruz（加州大学圣克鲁兹分校天文与天体物理系）；Max-Planck-Institut für extraterrestrische Physik (MPE)（马克斯·普朗克地外物理研究所）；NSF National Optical-Infrared Astronomy Research Laboratory（美国国家光学-红外天文研究实验室）；NRC Herzberg（加拿大国家研究委员会赫茨伯格研究所）
