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arXiv 2302.06647astro-ph.GA
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GA-NIFS:JWST/NIRSpec IFS揭示一个位于$z\sim5.55$低金属丰度活动星系核中的大质量黑洞

GA-NIFS: A massive black hole in a low-metallicity AGN at $z\sim5.55$ revealed by JWST/NIRSpec IFS

Hannah Übler, Roberto Maiolino, Emma Curtis-Lake, Pablo G. Pérez-González, Mirko Curti, Michele Perna, Santiago Arribas, Stéphane Charlot, Madeline A. Marshall,… 展开作者

Hannah Übler, Roberto Maiolino, Emma Curtis-Lake, Pablo G. Pérez-González, Mirko Curti, Michele Perna, Santiago Arribas, Stéphane Charlot, Madeline A. Marshall, Francesco D'Eugenio, Jan Scholtz, Andrew Bunker, Stefano Carniani, Pierre Ferruit, Peter Jakobsen, Hans-Walter Rix, Bruno Rodríguez Del Pino, Chris J. Willott, Torsten Böker, Giovanni Cresci, Gareth C. Jones, Nimisha Kumari, Tim Rawle

AI总结:

本文利用JWST/NIRSpec IFS数据确认$z=5.55$致密星系GS_3073为低金属丰度AGN,测得黑洞质量约$10^{8.2}M_\odot$,并发现其外流可在大爆炸后十亿年向星系际介质输送金属。

摘要:

我们展示了致密星系GS_3073(红移$z=5.55$)的JWST/NIRSpec积分场光谱仪静止坐标系光学数据。其在若干氢线和氦线中显著的宽成分(而在禁线中不存在),以及He II$\lambda4686$大等值宽度EW(He II)~20A的探测,明确将其识别为活动星系核(AGN)。我们测得气相金属丰度为$Z_{\rm gas}/Z_\odot\sim0.21^{+0.08}_{-0.04}$,低于在相似红移处更明亮的AGN以及更低红移AGN中所推断的值。我们经验性地表明,对于此类低金属丰度系统,经典发射线比值诊断图无法用于区分主要电离源(AGN或恒星形成),而涉及He II$\lambda4686$的不同诊断图则被证明非常有用,且与金属丰度无关。我们基于H$α$发射的宽线区光度和宽度,测得中心黑洞质量为$\log(M_{\rm BH}/M_\odot)\sim8.2\pm0.4$。虽然这使得GS_3073处于已知高红移黑洞质量的低端,但相对于其宿主星系性质,它仍然显得质量过大。我们探测到一个投影速度$\gtrsim700$ km/s的外流,并推断电离气体质量外流率约为$100\\ M_\odot/$yr,表明GS_3073能够在宇宙大爆炸后十亿年就使星系际介质富含金属。

英文摘要:

We present JWST/NIRSpec Integral Field Spectrograph rest-frame optical data of the compact $z=5.55$ galaxy GS_3073. Its prominent broad components in several hydrogen and helium lines (while absent in the forbidden lines), and the detection of a large equivalent width of He II$\lambda4686$, EW(He II) ~ 20A, unambiguously identify it as an active galactic nucleus (AGN). We measure a gas-phase metallicity of $Z_{\rm gas}/Z_\odot\sim0.21^{+0.08}_{-0.04}$, lower than what has been inferred for both more luminous AGN at similar redshift and lower redshift AGN. We empirically show that classical emission line ratio diagnostic diagrams cannot be used to distinguish between the primary ionisation source (AGN or star formation) for such low-metallicity systems, whereas different diagnostic diagrams involving He II$\lambda4686$ prove very useful, independent of metallicity. We measure the central black hole mass to be $\log(M_{\rm BH}/M_\odot)\sim8.2\pm0.4$ based on the luminosity and width of the broad line region of the H$α$ emission. While this places GS_3073 at the lower end of known high-redshift black hole masses, it still appears to be over-massive compared to its host galaxy properties. We detect an outflow with projected velocity $\gtrsim700$ km/s and infer an ionised gas mass outflow rate of about $100\ M_\odot/$yr, suggesting that GS_3073 is able to enrich the intergalactic medium with metals one billion years after the Big Bang.

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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