报告题目：Characterizing massive star-forming galaxies across the cosmic time through ALMA and JWST NIRCam grism spectroscopy

　　报告人：孙凤梧 博士（亚利桑那大学）

　　报告摘要：Over the past decade, our knowledge of the formation and evolution of massive galaxies has been greatly expanded with the Atacama Large Millimeter/submillimeter Array (ALMA). With its unprecedented sensitivity and angular resolution, I study the stellar and dust components of dusty star-forming galaxies (DSFGs) at z=1-6. At z=1-3, the majority of DSFGs host compact dust continuum emission when compared with their stellar components. However, this is not the case for certain DSFGs with relatively low millimeter surface brightness, and I provide a physical explanation for these systems. At z=3-6, the DSFG population is dominated by optical/near-IR-dark galaxies that are typically undetectable with the Hubble Space Telescope. These galaxies are compact in both stellar and dust components, tracing the early phase of massive galaxy formation. Such galaxies can also trace overdense galaxy environments and massive dark matter halos, which is demonstrated through my case study of HDF850.1 at z=5.18, the most luminous DSFG in the Hubble Deep Field.

　　With the James Webb Space Telescope (JWST), the study of galaxy formation at z>~6 has been rapidly revolutionized. I highlight my contribution to the successful commissioning and calibration of the wide-field slitless spectroscopy (WFSS) observing mode of JWST/NIRCam, which enables one of the first direct detections of rest-frame optical emission lines ([O III] 5007, Hα) from normal star-forming galaxies in the Epoch of Reionization (EoR). I obtain the first direct measurement of [O III] and Hα luminosity function at z>6, confirming the ubiquity of strong emission-line galaxies in the early Universe. I demonstrate that the NIRCam WFSS mode is highly efficient in spectroscopically confirming star-forming galaxies and large-scale overdense environments at high redshifts (z=5-9). This sheds light on highly complete spectroscopic surveys of galaxies towards the EoR, which will further transform our understanding of massive galaxy formation and evolution in the upcoming decade.

　　在过去十年中，阿塔卡玛大型毫米/亚毫米阵列 （ALMA） 极大地扩展了我们对大质量星系形成和演化的了解。凭借其前所未有的灵敏度和角分辨率，我研究了 z=1-6 处富尘产星星系 （DSFG） 的恒星和尘埃成分。 在z=1-3 ，与其恒星成分的大小相比，大多数 DSFG 的尘埃连续谱辐射都很致密。 然而，某些具有相对较低的毫米表面亮度的 DSFG并非如此，我为这些系统提供了物理解释。 在z=3-6，DSFG主要是光学/近红外暗的，这些星系通常无法用哈勃太空望远镜探测到。 它们的恒星和尘埃成分都很致密，表征了大质量星系形成的早期阶段。 此类星系还可以示踪高密度星系环境和大质量暗物质晕，这一点在我对HDF850.1（z=5.18；哈勃深场中最明亮的 DSFG）的案例研究中得到展示。

　　詹姆斯·韦布太空望远镜 （JWST）使得对z>6 处星系形成的研究发生了迅速而革命性的变化。 我将展示我对 JWST/NIRCam 的宽视场无缝光谱 （WFSS） 观测模式的成功调试和校准所做的贡献。这使得首次直接探测到来自宇宙再电离时代中正常产星星系的静止系光学波段发射线 （[O III] 5007、Hα）成为可能。 我首次直接测量了 z>6 处的 [O III] 和 Hα 光度函数，证实了早期宇宙中强发射线星系的普遍存在。 我证明了 NIRCam WFSS 模式对光谱认证高红移 （z=5-9） 产星星系和大尺度超密环境方面的极高效率。 这使得高度完备的再电离时代星系光谱巡天成为可能，或将进一步改变未来十年内我们对大质量星系形成和演化的理解。

　　报告时间：2023年6月25日（周日）10:00

　　报告地点：紫台仙林园区5-516

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