AI 中文总结
该研究利用CLAUDS和HSC-SSP数据，通过改进的深度学习框架探测近邻星系的恒星形成团块，测得团块型恒星形成星系占比随红移降低而下降，且与宿主星系恒星质量、sSFR存在特定关联。
AI 中文摘要
大质量的恒星形成团块是高红移（z > 1）星系中普遍观测到的恒星形成密集区域。低红移团块星系类似体的观测较为稀少，但宽场星系巡天数据的可用性使得探测大样本团块星系的可行性大幅提升。我们在红移z≤0.32的5395个恒星形成星系（SFGs）的质量完备样本中，探测到12790个恒星形成团块，这些星系位于Hyper Suprime-Cam Subaru战略巡天（HSC-SSP）和CFHT大天区U波段深场巡天（CLAUDS）观测的XMM-LSS、E-COSMOS和DEEP2-3天区。团块的探测采用了我们基于深度学习（DL）的目标检测框架的改进版本，该框架以ZOOBOT基础深度学习模型作为“骨干”特征提取器。我们基于团块定义（要求团块在CLAUDS U波段的星系流量比≥8%），确定了至少拥有一个偏心团块的恒星形成星系的占比（f_clumpy）。我们估计f_clumpy从z~0.3时的~31%降至z~0.1时的~23%，这与高红移观测测得的团块占比的低红移外推结果吻合良好。在固定红移下，f_clumpy与宿主星系的恒星质量呈负相关，与宿主星系的恒星形成率密度（sSFR）呈正相关。当团块定义改为仅包含恒星质量M_cl≥10^7 M☉的团块时，我们观测到团块占比大幅提升至~60%，该占比倾向于随宿主星系的恒星质量增加而增加，但与宿主星系的sSFR无关联。
英文摘要
Massive, star-forming clumps are regions of intensive star-formation that are commonly observed in high-redshift ($z > 1$) galaxies. Observations of low-redshift clumpy galaxy analogues are rare but the availability of wide-field galaxy survey data makes the detection of large clumpy galaxy samples much more feasible. We present a population of 12,790 star-forming clumps detected in a mass-complete sample of 5,395 star-forming galaxies (SFGs) at redshifts $z\leq0.32$, located in the XMM-LSS, E-COSMOS and DEEP2-3 fields observed by the Hyper Suprime-Cam Subaru Strategic Survey (HSC-SSP) and CFHT Large Area U-band Deep Survey (CLAUDS). The clumps were detected using an improved version of our Deep Learning (DL)-based object detection framework which uses the ZOOBOT foundation DL-model as a 'backbone' feature extractor. We determined the fraction of star-forming galaxies hosting at least one off-centre clump ($f_{\mathrm{clumpy}}$) based on a clump definition that requires a clump-galaxy flux ratio in the CLAUDS u-band of $\geq8\%$. We estimate $f_{\mathrm{clumpy}}$ to decrease from $\sim$31\% at $z\sim0.3$ to $\sim$23\% at $z \sim 0.1$, which aligns well with a low-redshift extrapolation of the clumpy fraction that is measured using high-redshift observations. At fixed redshift, $f_{\mathrm{clumpy}}$ is negatively correlated with the stellar mass and positively correlated with the specific star-formation rate (sSFR) of the host galaxies. When the clump definition is changed to include only clumps with a stellar mass of $M_{\mathrm{cl}} \geq 10^7 M_\odot$, we observe a highly increased clumpy fraction of $\sim$60\% that tends to increase with the stellar mass of the host galaxies but does not show a dependence on the sSFR of the host galaxies.
CommentsAccepted 2026 September 1 by MNRAS
