标题： 致密尘埃遮蔽的星形成以及星系双峰分布的起源 显示英文标题

标题： Compact dust-obscured star-formation and the origin of the galaxy bimodality

摘要： 在过去十年中，关于高度退化且质量巨大的红星形成星系（RedSFGs）的研究表明，在$z \sim 4$时它们可能构成了一个至关重要的群体，有助于揭示驱动从高红移处的活跃恒星形成向平静过渡的机制。 由于这种过渡似乎与形态变化有关，研究这些RedSFGs的形态特性对于理解星系演化至关重要。 为此，我们正在使用CEERS调查中的JWST/NIRCam图像来构建一个在$z=3-4$时具有完整质量样本的188个巨大星系，对其执行了解决后的光谱能量分布拟合。 在将星系分类为典型的蓝色星形成星系（BlueSFGs）、RedSFGs和安静星系（QGs）之后，我们比较了每个星系群体在恒星质量密度、SFR密度、sSFR、尘埃消光和质量加权年龄方面的形态学特征。 我们发现RedSFGs和QGs呈现出相似的恒星表面密度分布，并且RedSFGs表现出的尘埃消光集中度显著高于BlueSFGs的所有质量范围。 这表明一旦蓝色星形成星系变得足够大，它必须经历一个主要的收缩阶段才能变为安静。 同时，我们发现RedSFGs和QGs占这个红移处具有${\rm log}(M_\ast/M_\odot)> 10.4$星系的$50\%$以上。 这一转变质量对应于在本地宇宙中区分蓝色星形成星系和安静星系双峰性的“临界质量”。 然后我们得出结论，延伸的蓝色星形成星系和经过重大气体压缩阶段的紧凑、高度衰减的红色星形成星系之间存在双峰性，后者能够就地建立一个巨大的灯泡。 有证据表明，这一早期分离是本地宇宙中蓝色星形成星系和安静星系双峰性起源的原因，我们称之为“原始双峰性”。 显示英文摘要

摘要： During the last decade, studies about highly attenuated and massive red star-forming galaxies (RedSFGs) at $z \sim 4$ have suggested that they could constitute a crucial population for unraveling the mechanisms driving the transition from vigorous star formation to quiescence at high redshifts. Since such a transition seems to be linked to a morphological transformation, studying the morphological properties of these RedSFGs is essential to our understanding of galaxy evolution. To this end, we are using JWST/NIRCam images from the CEERS survey to assemble a mass-complete sample of 188 massive galaxies at $z=3-4$, for which we perform resolved-SED fit. After classifying galaxies into typical blue SFGs (BlueSFGs), RedSFGs and quiescent galaxies (QGs), we compare the morphologies of each population in terms of stellar mass density, SFR density, sSFR, dust-attenuation and mass-weighted age. We find that RedSFGs and QGs present similar stellar surface density profiles and that RedSFGs manifest a dust attenuation concentration significantly higher than that of BlueSFGs at all masses. This indicates that to become quiescent, a BlueSFG must transit through a major compaction phase once it has become sufficiently massive. At the same time, we find RedSFGs and QGs to account for more than $50\%$ of galaxies with ${\rm log}(M_\ast/M_\odot)> 10.4$ at this redshift. This transition mass corresponds to the "critical mass" delineating the bimodality between BlueSFGs and QGs in the local Universe. We then conclude that there is a bimodality between extended BlueSFGs and compact, highly attenuated RedSFGs that have undergone a major gas compaction phase enabling the latter to build a massive bulb in situ. There is evidence that this early-stage separation is at the origin of the local bimodality between BlueSFGs and QGs, which we refer to as a "primeval bimodality".