发表机构
Finnish Centre for Astronomy with ESO, (FINCA), University of Turku; Tuorla Observatory, Department of Physics and Astronomy, University of Turku; Turku Collegium for Science, Medicine and Technology (TCSMT), University of Turku; European Southern Observatory; Sub-Department of Astrophysics, Department of Physics, University of Oxford; INAF – Osservatorio Astronomico di Capodimonte; INAF – Osservatorio Astronomico di Roma; Instituto de Astrofísica de Canarias（图尔库大学芬兰ESO天文学中心; 图尔库大学图奥拉天文台; 图尔库大学图尔库科学、医学与技术学院; 欧洲南方天文台; 牛津大学物理系天体物理子部门; 意大利国家天体物理研究所卡波迪蒙特天文台; 意大利国家天体物理研究所罗马天文台; 加那利群岛天体物理研究所）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
利用MUSE+AO空间分辨光谱研究遗迹星系J1447-0149，揭示其旋转恒星结构包裹的古老高色散核，并确认其遗迹本质。
AI 中文摘要
遗迹星系是高红移致密静止星系的演化后裔。我们展示了J1447-0149（一个位于$z=0.21$的大质量遗迹星系）的首个空间分辨光谱研究，该星系由MUSE+AO观测。我们表征了其运动学和恒星种群性质，以探测其空间分辨的质量组装历史。我们以亚千秒差距的bin尺寸测量了恒星运动学，覆盖约$1.4$个有效半径。随后，我们利用由运动学信息指导的较粗的三bin配置，恢复了更高阶的速度矩、$[\alpha/{\rm Fe}]$、恒星年龄和金属丰度。我们重建了恒星形成历史并计算了遗迹度（DoR）。MUSE数据揭示了一个速度梯度，表明J1447-0149并非纯粹由压力支撑。速度弥散场呈现中心峰值，达到$\sigma_\star=233\pm13\\,{\rm km\\,s^{-1}}$，显著大于此前受视宁度限制的测量值（$\sigma_{\star} =187 \pm 9\\,{\rm km\\,s^{-1}}$）。$h_3$–$V_\star$反相关和轻微正的$h_4$值支持复合结构，即一个旋转恒星成分包围着一个致密动力学热核。这个中心、弥散主导的区域也是最古老且金属丰度最高的成分。其恒星形成历史迅速上升，恒星质量在大爆炸后约$2\\,{\rm Gyr}$内组装完成，并达到${\rm DoR}=0.9^{+0.1}_{-0.2}$。两个外部bin的DoR值为${\rm DoR}=0.8\pm0.2$，与中心bin一致，但可能表明形成时间略长。空间分辨光谱对于确认J1447-0149的遗迹本质至关重要，将分辨形态、运动学和恒星种群联系起来，以约束其中心球状体和周围盘面的早期组装。
英文摘要
Relic galaxies are the descendants of high-redshift compact quiescent systems. We present the first spatially resolved spectroscopic study of J1447-0149, a massive relic at $z=0.21$, observed with MUSE+AO. We characterize its kinematics and stellar population properties to probe its spatially resolved mass assembly history. We measured stellar kinematics with sub-kpc bin sizes, covering $\sim 1.4$ effective radii. We then used a coarser three-bin configuration informed by the kinematics to recover the higher-order velocity moments, $[α/{\rm Fe}]$, stellar age and metallicity. We reconstructed the star formation history and computed the degree of relicness (DoR). MUSE data reveal a velocity gradient, showing that J1447-0149 is not purely pressure supported. The velocity-dispersion field displays a central peak, reaching $σ_\star=233\pm13\,{\rm km\,s^{-1}}$, substantially larger than previous seeing-limited measurements ($σ_{\star} =187 \pm 9\,{\rm km\,s^{-1}}$). The $h_3$--$V_\star$ anti-correlation and mildly positive $h_4$ values support a composite structure, with a rotating stellar component surrounding a compact dynamically hot core. This central, dispersion-dominated region is also the oldest and most metal-rich component. Its SFH rises rapidly, with the stellar mass assembled within $\sim2\,{\rm Gyr}$ after the Big Bang, and reaches ${\rm DoR}=0.9^{+0.1}_{-0.2}$. The two outer bins have a DoR value of ${\rm DoR}=0.8\pm0.2$, consistent with the central bin, but possibly indicating slightly longer formation times. Spatially resolved spectroscopy has been crucial to confirm the relic nature of J1447-0149, linking resolved morphology, kinematics, and stellar populations to constrain the early assembly of its central spheroid and surrounding disk.
CommentsSubmitted to A&A, 14 pages, abstract abridged to fit arxiv limit
