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Publications
- Title
- ODIN: Confirmation and 3D Reconstruction of Six Massive Protoclusters at Cosmic Noon
- KIAS Author
- Park, Changbom
- Journal
- ASTROPHYSICAL JOURNAL, 2026
- Archive
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- Abstract
- Protoclusters represent sites of accelerated galaxy formation and extreme astrophysical activity characteristic of dense environments. Identifying massive protoclusters and mapping their spatial structures are therefore crucial for understanding how large-scale environment influences galaxy evolution. We combine wide-field Ly alpha imaging from the One-hundred-deg2 DECam Imaging in Narrowbands survey with extensive Dark Energy Spectroscopic Instrument and ancillary spectroscopy across the extended COSMOS and XMM Large Scale Structure (LSS) fields (approximate to 14 deg2) to search for massive protoclusters. We confirm six systems at z approximate to 2.4 and approximate to 3.1, including three newly identified structures and three which overlap with previously known structures and/or systems detected using other tracers. We reconstruct their three-dimensional structures, estimate descendant halo masses, and for one structure at z approximate to 3.12, demonstrate that overlapping narrowband filters (NB497 and N501) provide accurate redshift tomography for emission-line galaxies. One protocluster at z approximate to 2.45 overlaps with one of the LATIS tomographic fields, enabling direct comparison between galaxy and H i overdensities traced by Ly alpha forest absorption. Another at z approximate to 3.12 hosts a massive quiescent galaxy (M* approximate to 1.2 & times; 1011M circle dot), suggesting that overdense environments may play a role in accelerating galaxy assembly and quenching. Comparing Ly alpha emission properties across environments, we find that protocluster galaxies exhibit higher median line fluxes and a deficit of faint emitters relative to the field. The effect is strongest when combining 2D and 3D density information, indicating that galaxies in the densest protocluster cores are most affected by environmental processes. This effect is stronger at z approximate to 3.1 than at z approximate to 2.4, suggesting possible redshift evolution.
