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arXiv 2407.01889astro-ph.GA
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ALMA揭示z = 0.2340处FRB 20191001A宿主星系中分子气体的空间分辨性质

ALMA reveals spatially-resolved properties of molecular gas in the host galaxy of FRB 20191001A at z = 0.2340

Itsuki Yamanaka, Bunyo Hatsukade, Fumi Egusa, Tetsuya Hashimoto, Yuu Niino, Tzu-Yin Hsu, Hiroyuki Kaneko, Kotaro Kohno

AI总结:

本文利用ALMA首次在宇宙学距离上对FRB 20191001A宿主星系进行空间分辨CO观测,发现其分子气体质量和恒星形成率显著高于其他FRB宿主,且气体盘以有序旋转为主,支持FRB前身天体可存在于多种星系环境。

摘要:

我们利用阿塔卡马大型毫米/亚毫米波阵列(ALMA)报告了在红移z=0.2340的快速射电暴(FRB)FRB 20191001A宿主星系中探测到CO(2-1)发射线,空间分辨率为0.9角秒(3.5 kpc)。这是首次在宇宙学距离上对FRB宿主星系进行空间分辨的CO发射探测。该宿主星系的分子气体质量推断为(2.3±0.4)×10^10 M⊙,表明其富含气体,测得的分子气体分数μ_gas=0.50±0.22也证明了这一点。该分子气体质量以及宿主星系的恒星形成率SFR=8.06±2.42 M⊙ yr^-1,与其他FRB宿主星系中观测到的平均值M_gas=9.6×10^8 M⊙和SFR=0.90 M⊙ yr^-1不同。这进一步支持了FRB可能起源于多种星系环境中的单一或多个前身天体的假说。基于观测到的速度场建模,我们发现该分子气体盘以有序的圆周旋转为主,尽管该宿主星系有一个富含气体的伴星系,投影间距约为25 kpc。FRB前身天体的形成可能并非由这次相互作用触发。我们推导出在FRB探测位置处分子气体柱密度的3σ上限为< 2.1×10^21 cm^-2。

英文摘要:

We report the detection of the CO(2-1) emission line with a spatial resolution of 0.9 arcsec ($3.5 \mathrm{kpc}$) from the host galaxy of the fast radio burst (FRB), FRB 20191001A at $z=0.2340$, using the Atacama Large Millimeter/submillimeter Array. This is the first detection of spatially resolved CO emission from the host galaxy of an FRB at a cosmological distance. The inferred molecular gas mass of the host galaxy is $(2.3\pm0.4)\times10^{10} \mathrm{M_\odot}$, indicating that it is gas-rich, as evidenced by the measured molecular gas fraction $μ_\mathrm{gas}=0.50\pm0.22$. This molecular-gas mass and the star formation rate of the host, $\mathrm{SFR}=8.06\pm2.42 \mathrm{M_\odot yr^{-1}}$, differ from those observed in the other FRB host galaxies with the average $M_\mathrm{gas}=9.6\times10^8 \mathrm{M_\odot}$ and $\mathrm{SFR}=0.90 \mathrm{M_\odot yr^{-1}}$. This lends further credibility to the hypothesis that FRBs may originate from single or multiple progenitors across a diverse range of galaxy environments. Based on the observed velocity field modeling, we find that the molecular gas disk is dominated by an ordered circular rotation, despite the fact that the host galaxy has a gas-rich companion galaxy with a projected separation of $\sim 25 \mathrm{kpc}$. The formation of the FRB's progenitor might not have been triggered by this interaction. We derive the 3$σ$ upper limit of the molecular gas column density at the FRB detection site to be $< 2.1\times 10^{21} \mathrm{cm^{-2}}$ with a 3$σ$ upper limit.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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