近日，美国加州理工学院的Kritti Sharma及其研究团队取得一项新进展。经过不懈努力，他们发现快速射电暴更倾向于出现在大质量恒星形成星系中。相关研究成果已于2024年11月6日在国际权威学术期刊《自然》上发表。

本文介绍了由深空同步阵列（DSA-110）发现的30个快速射电暴（FRB）宿主星系的恒星星族特性。分析表明，与宇宙中的恒星形成活动相比，低质量FRB宿主星系明显不足，这意味着FRB是恒星形成的一个有偏追踪器，更倾向于选择大质量的恒星形成星系。这种偏差可能是由星系金属丰度驱动的，因为金属丰度与恒星质量呈正相关。

金属丰富的环境可能通过恒星合并来促进磁星前身的形成，因为金属丰度较高的恒星结构较松散，更容易充满其洛希瓣，从而导致不稳定的质量转移。虽然大质量恒星没有产生强磁场的对流内部结构，但合并残骸被认为具有形成磁星所需的内部磁场强度。FRB更倾向于出现在大质量恒星形成星系中，这表明合并残骸的核心坍缩超新星更倾向于形成磁星。

据悉，快速射电暴（FRB）是从银河系外探测到的毫秒级事件。快速射电暴的发射特征表明，其源头很可能是高度磁化的中子星，即磁星，这一推测得到了来自银河系内磁星的类似快速射电暴爆发以及快速射电暴宿主星系具有恒星形成特性的支持。

然而，产生快速射电暴源的过程仍然未知。尽管银河系内的磁星通常与核坍缩超新星（CCSNe）相关联，但尚不确定是哪些超新星会演化成磁星。因此，可以通过研究快速射电暴源所处的银河系环境来探究其前身星。

附：英文原文

Title: Preferential occurrence of fast radio bursts in massive star-forming galaxies

Author: Sharma, Kritti, Ravi, Vikram, Connor, Liam, Law, Casey, Ocker, Stella Koch, Sherman, Myles, Kosogorov, Nikita, Faber, Jakob, Hallinan, Gregg, Harnach, Charlie, Hellbourg, Greg, Hobbs, Rick, Hodge, David, Hodges, Mark, Lamb, James, Rasmussen, Paul, Somalwar, Jean, Weinreb, Sander, Woody, David, Leja, Joel, Anand, Shreya, Das, Kaustav Kashyap, Qin, Yu-Jing, Rose, Sam, Dong, Dillon Z., Miller, Jessie, Yao, Yuhan

Issue&Volume: 2024-11-06

Abstract: Fast radio bursts (FRBs) are millisecond-duration events detected from beyond the Milky Way. FRB emission characteristics favour highly magnetized neutron stars, or magnetars, as the sources, as evidenced by FRB-like bursts from a galactic magnetar, and the star-forming nature of FRB host galaxies. However, the processes that produce FRB sources remain unknown. Although galactic magnetars are often linked to core-collapse supernovae (CCSNe), it is uncertain what determines which supernovae result in magnetars. The galactic environments of FRB sources can be used to investigate their progenitors. 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 dynamo, 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.

DOI: 10.1038/s41586-024-08074-9

Source: https://www.nature.com/articles/s41586-024-08074-9