Diverse Properties of Molecular Gas in the Host Galaxies of Fast Radio Bursts
Diverse Properties of Molecular Gas in the Host Galaxies of Fast Radio Bursts
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DOI：
10.3847/2041-8213/ac9f39
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发表时间：
2022-11
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影响因子：
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通讯作者：
B. Hatsukade;T. Hashimoto;Y. Niino;Tzu-Yin Hsu
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作者：
B. Hatsukade;T. Hashimoto;Y. Niino;Tzu-Yin Hsu
利用阿塔卡玛大型毫米/亚毫米波射电望远镜阵对6个快射电暴（FRB）的宿主星系进行了CO观测（FRB 20180924 B，20190102 C和20190711 A），矮星系中一个未检测到的结果（FRB 20121102 A），以及在M81（FRB 20200120 E）和银河系（FRB 20200428 A）中检测到的两个事件。CO观测结果导致在FRB 20180924 B宿主中检测到CO（3-2）排放，而在FRB 20190102 C和FRB 20190711 A宿主中分别未检测到CO（3-2）和CO（2-1）排放。FRB 20180924 B、FRB 20190102 C和FRB 20190711 A的分子气体质量和3σ上限分别为（2.4 ± 0.2）× 109 M、<3.8 × 108 M和<6.7 × 109 M。我们发现样品中分子气体性质（气体质量，气体耗尽时间和气体与恒星质量的比例）的多样性。与其他恒星形成星系相比，FRB 20180924 B宿主富含气体（较大的分子气体分数），而FRB 20190102 C和FRB 20200120 E的宿主气体贫乏，其恒星质量和星星形成速率的耗尽时间较短。我们的研究结果表明，FRB来自多个祖先或单个祖先，可以存在于广泛的星系环境中。统计分析表明，FRB宿主星系和本地恒星形成星系之间的分子气体分数的分布有显着差异。然而，当排除离群值（FRB 20200120 E主机）时，差异并不显着，并且需要使用更大的样本进行分析。
We report the properties of molecular gas in a sample of six host galaxies of fast radio bursts (FRBs) obtained from CO observations with the Atacama Large Millimeter/submillimeter Array (FRBs 20180924B, 20190102C, and 20190711A), the results of one nondetection in a dwarf galaxy (FRB 20121102A), and two events detected in M81 (FRB 20200120E) and the Milky Way (FRB 20200428A). The CO observations resulted in the detection of CO(3–2) emission in the FRB 20180924B host and nondetections of CO(3–2) and CO(2–1) emission in the hosts of FRB 20190102C and FRB 20190711A, respectively. The derived molecular gas mass and 3σ upper limit is (2.4 ± 0.2) × 109 M ⊙, <3.8 × 108 M ⊙, and <6.7 × 109 M ⊙ for the hosts of FRB 20180924B, FRB 20190102C, and FRB 20190711A, respectively. We found diversity in molecular gas properties (gas mass, gas depletion time, and gas fraction to stellar mass) in the sample. Compared to other star-forming galaxies, the FRB 20180924B host is gas-rich (the larger molecular gas fraction), and the hosts of FRB 20190102C and FRB 20200120E are gas-poor with a shorter depletion time for their stellar mass and star formation rate. Our findings suggest that FRBs arise from multiple progenitors or single progenitors that can exist in a wide range of galaxy environments. Statistical analysis shows a significant difference in the distribution of molecular gas fraction between the FRB hosts and local star-forming galaxies. However, the difference is not substantial when an outlier, the FRB 20200120E host, is excluded, and analysis with a larger sample is needed.