大質量銀河に関連する強力な電波バースト(Mighty Radio Bursts Linked to Massive Galaxies)

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2024-11-06 カリフォルニア工科大学(Caltech)

カリフォルニア工科大学の研究者は、強力な高速電波バースト(FRBs)が大質量銀河と関連していることを発見しました。これらのFRBsは、宇宙の遠く離れた領域から短時間に発生する高エネルギーの電波信号であり、以前は主に小型銀河で観測されていました。しかし、今回の発見により、大質量銀河もFRBsの源として重要である可能性が示唆され、宇宙の構造や銀河の性質に関する理解が深まりました。

<関連情報>

大質量星形成銀河における高速電波バーストの優先的発生 Preferential occurrence of fast radio bursts in massive star-forming galaxies

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
Nature  Published:06 November 2024
DOI:https://doi.org/10.1038/s41586-024-08074-9

大質量銀河に関連する強力な電波バースト(Mighty Radio Bursts Linked to Massive Galaxies)

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 sources1, as evidenced by FRB-like bursts from a galactic magnetar2,3, and the star-forming nature of FRB host galaxies4,5. However, the processes that produce FRB sources remain unknown6. Although galactic magnetars are often linked to core-collapse supernovae (CCSNe)7, 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 mass8. Metal-rich environments may favour the formation of magnetar progenitors through stellar mergers9,10, 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 magnetars11,12. The preferential occurrence of FRBs in massive star-forming galaxies suggests that a core-collapse supernova of merger remnants preferentially forms magnetars.

1701物理及び化学
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