▲ 作者:Kritti Sharma, Vikram Ravi, Liam Connor, Casey Law, Stella Koch Ocker, Myles Sherman, Nikita Kosogorov, Jakob Faber, Gregg Hallinan, Charlie Harnach, Greg Hellbourg, Rick Hobbs, David Hodge, Mark Hodges, James Lamb, Paul Rasmussen, Jean Somalwar, Sander Weinreb, David Woody, Joel Leja, Shreya Anand, Kaustav Kashyap Das, Yu-Jing Qin, Sam Rose,Yuhan Yao
▲ 链接:
https://www.nature.com/articles/s41586-024-08074-9
▲ 摘要:
快速射电暴(FRB)是从银河系之外探测到的毫秒级天文事件。研究展示了由深天气阵列(DSA-110)发现的30个FRB宿主星系的恒星种群特性。该分析显示,与宇宙中恒星形成的发生相比,低质量FRB宿主明显不足。这意味着FRB是一种有偏差的恒星形成示踪剂,优先选择大质量的恒星形成星系。
这种偏差可能是由星系的金属丰度造成的,而金属丰度与恒星质量正相关。富含金属的环境可能有利于通过恒星合并形成磁星祖先。因为金属丰度较高的恒星不太紧凑,更有可能填满它们的罗氏叶,导致不稳定的质量传递。
尽管大质量恒星的内部没有对流,无法通过发电机产生强大的磁场,但人们认为,合并残留物具有形成磁星所必需的内部磁场强度。FRB优先出现在大质量恒星形成星系中,这表明合并残留物的核心坍缩超新星会优先形成磁星。
▲ Abstract:
Fast radio bursts (FRBs) are millisecond-duration events detected from beyond the Milky Way. Here, we present the stellar population properties of 30 FRB host galaxies discovered by the Deep Synoptic Array (DSA-110). Our analysis shows a marked deficit of low-mass FRB hosts compared with the occurrence of star formation in the Universe, implying that FRBs are a biased tracer of star formation, preferentially selecting massive star-forming galaxies. This bias may be driven by galaxy metallicity, which is positively correlated with stellar mass. Metal-rich environments may favour the formation of magnetar progenitors through stellar mergers, as higher-metallicity stars are less compact and more likely to fill their Roche lobes, leading to unstable mass transfer. Although massive stars do not have convective interiors to generate strong magnetic fields by dynamo11, merger remnants are thought to have the requisite internal magnetic-field strengths to result in magnetars. The preferential occurrence of FRBs in massive star-forming galaxies suggests that a core-collapse supernova of merger remnants preferentially forms magnetars.