发表机构
Universidad de Valparaíso; Millenium Nucleus for Galaxies (MINGAL); STAR Institute; Université Côte d’Azur; University of Florida; Universidad Nacional Autónoma de México; Instituto Nacional de Astrofísica Óptica y Electrónica (INAOE); Universidad Central de Chile（瓦尔帕莱索大学; 星系千年核（MINGAL）; STAR研究所; 蔚蓝海岸大学; 佛罗里达大学; 墨西哥国立自治大学; 国家天体物理学、光学和电子学研究所; 智利中央大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
通过ALMA和JWST对强透镜星系SMMJ0658的观测，在亚千秒差距尺度检验KS关系，发现其瓦解尺度为0.8千秒差距，表明KS关系的普适性在解析单个恒星形成区域时失效。
AI 中文摘要
恒星形成是驱动星系演化的关键过程，但理解其在星际介质（ISM）中的进行方式需要在亚千秒差距尺度上解析冷分子气体和尘埃。在z~2-3，即宇宙恒星形成峰附近，这种分辨率通常只能通过强引力透镜实现。我们介绍了对SMMJ0658的ALMA研究，这是一个被子弹星系团（z=0.296）透镜成三个像的20倍放大主序恒星形成星系，红移为z=2.7768±0.0002。我们使用0.2角秒和0.6角秒的ALMA 3波段观测来检验宇宙正午时期亚千秒差距尺度上的Kennicutt-Schmidt（KS）关系。利用基于JWST的子弹星系团强透镜模型，我们重建了源平面CO(3-2)和静止系803微米尘埃连续谱图，分辨率低至约200秒差距。我们推导了空间分辨的分子气体和恒星形成率面密度、消耗时标以及200秒差距至3.2千秒差距孔径上CO与尘埃通量比的尺度依赖性。0.2角秒的ALMA数据揭示了巨大而致密的恒星形成团块，其Sigma_mol约为1.3-2.3×10^3太阳质量每平方秒差距，Sigma_SFR约为0.5-2.3太阳质量每年每千秒差距平方，tau_dep约为0.82-2.56吉年。CO与尘埃的空间去相关产生了tau_dep的强烈尺度依赖性。我们发现KS关系瓦解尺度为0.8±0.1千秒差距，与各个区域追踪恒星形成周期不同阶段相一致。ALMA和JWST数据还揭示了z~2.78处一个透镜星系对的证据，尽管SMMJ0658是否正在经历早期相互作用仍不确定。我们的结果表明，一旦单个恒星形成区域被空间分辨，KS关系的表观普适性就会瓦解，这与从本地宇宙到z~1的观测一致。我们将这一图景扩展到z~2.78，为解析团块状冷ISM的性质和宇宙正午时期的恒星形成周期提供了新见解。
英文摘要
[abridged] Star formation is a key process driving galaxy evolution, but understanding how it proceeds within the interstellar medium (ISM) requires resolving cold molecular gas and dust on sub-kpc scales. At z~2-3, near the peak of cosmic star formation, such resolution can generally only be achieved through strong gravitational lensing. We present an ALMA study of SMMJ0658, a 20x-magnified main-sequence star-forming galaxy at z=2.7768 +/- 0.0002, lensed by the Bullet Cluster (z=0.296) into three images. We use 0.2" and 0.6" ALMA Band-3 observations to test the Kennicutt-Schmidt (KS) relation at sub-kpc scales at cosmic noon. Using a JWST-based strong-lensing model of the Bullet Cluster, we reconstruct source-plane CO(3-2) and rest-frame 803um dust-continuum maps down to ~200pc scales. We derive spatially resolved molecular gas and star formation rate surface densities, depletion times, and the scale dependence of the CO-to-dust flux ratio over 200pc-3.2kpc apertures. The 0.2" ALMA data reveal massive, dense star-forming clumps, with Sigma_mol ~1.3-2.3 x 10^3 M_sun pc^-2, Sigma_SFR ~0.5-2.3 M_sun yr^-1 kpc^-2, and tau_dep ~0.82-2.56 Gyr. CO-dust spatial decorrelation produces a strong scale dependence in tau_dep. We find a KS-relation breakdown scale of 0.8 +/- 0.1 kpc, consistent with individual regions tracing distinct stages of the star-formation cycle. The ALMA and JWST data also reveal evidence for a lensed galaxy pair at z~2.78, although whether SMMJ0658 is undergoing an early-stage interaction remains uncertain. Our results show that the apparent universality of the KS relation breaks down once individual star-forming regions are spatially resolved, in line with observations from the local universe to z~1. We extend this picture to z~2.78, providing new insight into the resolved properties of the clumpy cold ISM and the star-formation cycle at cosmic noon.
CommentsRecommended for publication in A&A with minor revisions. We have uploaded the revised manuscript to arXiv
