Insights into Galaxy Morphology and Star Formation: Unveiling Filamentary Structures around an Extreme Overdensity at z ∼ 1.5 Traced by [O II] Emitters

April 2024 • 2024ApJ...964L..33L

Authors • Laishram, Ronaldo • Kodama, Tadayuki • Morishita, Takahiro • Faisst, Andreas • Koyama, Yusei • Yamamoto, Naoaki

Abstract • We explore the morphological features and star formation activities of [O II] emitters in the COSMOS UltraDeep field at z ∼ 1.5 using JWST NIRCam data from the COSMOS-Web survey and Subaru Hyper Suprime-Cam. We also report the discovery of large filamentary structures traced by [O II] emitters surrounding an extremely overdense core with a galaxy number density ∼11× higher than the field average. These structures span over 50 cMpc, underscoring their large scale in the cosmic web at this epoch. After matching the stellar-mass distributions, the core galaxies show a higher frequency of disturbances (50% ± 9%) than those in the outskirts (41% ± 9%) and the field (21% ± 5%), indicative of more frequent mergers and interactions in the innermost ≲1.'5 region. Additionally, we observe that specific star formation rates are elevated in denser environments. A Kolmogorov–Smirnov test comparing the distribution of specific star formation rates of core and field galaxies yields a p-value of 0.02, suggesting an enhancement of star formation activity driven by the dense environment. Our findings underscore the environmental impact on galaxy evolution during a pivotal cosmic epoch and set the stage for further investigation with the increasing larger data from upcoming surveys.

Links

• SIMBAD http://simbad.u-strasbg.fr/simbo.pl?bibcode=2024ApJ...964L..33L
• PDF https://iopscience.iop.org/article/10.3847/2041-8213/ad3238/pdf
• PREPRINT http://arxiv.org/abs/2403.06369
• DATA https://archive.stsci.edu/mastbibref.php?bibcode=2024ApJ...964L..33L
• ELECTR https://doi.org/10.3847%2F2041-8213%2Fad3238