JWST/NIRSpec积分场单元观测揭示z=9.31处一个动力学活跃的相互作用星系中不同的电离气体条件
Diverse ionized gas conditions in a dynamically hot, interacting galaxy at $z = 9.31$ revealed by JWST/NIRSpec IFU
AI总结：
本研究通过JWST观测z=9.31的相互作用星系Gz9p3，揭示其核与尾区电离气体性质差异，证实该星系为动力学活跃系统且正处于星系喷泉阶段。
AI中文摘要：
我们利用詹姆斯·韦伯空间望远镜NIRSpec/G395H积分场单元（IFU）的高光谱分辨率（R≈2700）模式观测，对红移z=9.31的相互作用星系Gz9p3开展了空间和光谱分辨研究。Gz9p3由“核”和“尾”两个子区域组成，二者物理性质存在显著差异：核区的HII区具有高电子密度（nₑ≳2900 cm⁻³）、低气体相金属度（比质量-金属度关系低0.25 dex），且该系统中的恒星形成率（sSFR）相对较低；而尾区则呈现低电子密度（nₑ<70 cm⁻³）、与质量-金属度关系一致的相对高气体相金属度，以及高sSFR。因此，积分光谱呈现出介于这两个区域之间的性质。未发现电离气体存在有序旋转的证据，表明Gz9p3是一个动力学活跃的系统。最后，我们发现整个系统大部分区域存在由[OIII]5007次线成分表征的电离气体外流，外流速度低于逃逸速度，使Gz9p3成为首批经历星系喷泉的星系系统之一。总体而言，我们的发现表明，该系统正处于星系相互作用后，原始气体高效落入核区、稀释气体金属度并增强恒星形成与外流的阶段。
英文摘要：
We present a spatially and spectrally resolved study of an interacting galaxy, Gz9p3 at $z=9.31$, using the James Webb Space Telescope NIRSpec/G395H IFU observation with high-spectral resolution ($R\approx 2700$) mode. Gz9p3 consists of two sub-regions (`core' and `tail'), which show stark contrast in their physical properties. The HII regions in the core are characterized by high electron density ($n_{e}\gtrsim2900$ cm$^{-3}$), low gas-phase metallicity ($0.25$ dex below the mass-metallicity relation), and yet relatively low specific star formation rate (sSFR) among the system. On the other hand, the tail exhibits low electron density ($n_{e}<70$ cm$^{-3}$), relatively high gas-phase metallicity that is consistent with the mass-metallicity relation, and high sSFR. The integrated spectrum thus shows the properties inbetween these two regions. No evidence of ordered rotation in ionized gas is found, suggesting that Gz9p3 is a dynamically hot system. Finally, we find ionized gas outflows characterized by the secondary [OIII]5007 line component throughout most of the system. The outflow velocity is below the escape velocity, making Gz9p3 one of the first galactic systems experiencing a galactic fountain. Overall, our findings indicate that this system is in a phase in which the pristine gas is falling efficiently into the core, diluting the gas metallicity, and enhancing star formation and outflows after the galaxy interaction.
