Hatamnia et al 2025 ================================================================================ Large-Scale Structure in COSMOS-Web: Tracing Galaxy Evolution in the Cosmic Web up to z ~ 7 with the Largest JWST Survey Hossein Hatamnia, Bahram Mobasher, Sina Taamoli, Jeyhan S. Kartaltepe, Caitlin M. Casey, Hollis B. Akins, Malte Brinch, Nima Chartab, Andreas L. Faisst, Steven L. Finkelstein, Maximilien Franco, Finn Giddings, Ghassem Gozaliasl, Ali Hadi, Aryana Haghjoo, Santosh Harish, Olivier Ilbert, Pascale L. Jablonka, Shuowen Jin, Ali Ahmad Khostovan, Anton M. Koekemoer, Ronaldo Laishram, Daizhong Liu, Matteo Maturi, Henry Joy McCracken, Crystal L. Martin, Lauro Moscardini, Diana Scognamiglio, Marko Shuntov, Greta Toni, Alexander de la Vega, John R. Weaver, Lilan Yang, = ================================================================================ Keywords: large-scale structure of Universe; galaxies: evolution; galaxies: high-redshift; galaxies: clusters; methods: data analysis Abstract: We reconstruct large-scale structure using the James Webb Space Telescope COSMOS-Web program to trace environmentally driven galaxy evolution up to z ~ 7. We apply a weighted kernel density estimation method to ~160,000 galaxies with robust photometric redshifts. Stellar mass correlates positively with density at all redshifts, most strongly for quiescent galaxies at z <= 2.5; at higher redshift (2.5 <= z <= 5.5) this trend appears mainly in extreme overdensities, consistent with early mass assembly in protoclusters. The star- formation rate shows a negative trend with density for quiescent systems at z <= 1.2 and reverses at z >= 1.8; star-forming galaxies show a mild positive correlation up to z ~ 5.5. Specific SFR is roughly flat for star-forming galaxies and declines with density for quiescent systems at z <= 1.2. Mass and environmental quenching efficiencies indicate mass-driven processes dominate at z >= 2.5, both effects are comparable for 0.8 <= z <= 2.5, and environment dominates for low-mass galaxies (M* <= 1e10 Msun) at z <= 0.8. COSMOS-Web provides deep photometric redshifts and reaches ~80% mass completeness at log10(M*/Msun) ~ 8.7 at z = 7. Description: Description: The FITS file contains two binary tables (SLICES and POINTS), one per-object overdensity table (OVERDENSITY), and per-slice 2D density map images. SLICES lists the slice index, central redshift z, KDE bandwidth scale b, and the median slice density bg_dens. POINTS lists all galaxies per slice with RA and Dec in the sky frame, x and y in the internal rotated frame, the per-slice weight w, the adaptive kernel bandwidth adaptive_b, and the edge correction factor boundary_corr. OVERDENSITY provides one row per galaxy id with RA, Dec, and the per-object overdensity value density_excess, equal to 1 + delta, computed from the KDE density field. The 2D density maps are stored as image HDUs: DENSITY_###, DENSITYCONTRAST_###, and DENSITYEXCESS_### in the sky frame aligned with RA and Dec; and DensityRotated_###, DensityContrastRotated_###, and DensityExcessRotated_### in the rotated frame. Each image HDU header includes SLICE, Z, B, BG_DENS, and IMTYPE. The primary header reports NSLICE and NOBJ. File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file SLICES 51 314 Per-slice metadata: index, z_center, bandwidth scale, median density POINTS 148 2188547 Per-slice source points with RA, Dec, weights, adaptive bandwidth, boundary correction OVERDENSITY 58 164155 Per-object overdensity table: COSMOS2025 id, RA, Dec, and density_excess = 1 + delta -------------------------------------------------------------------------------- Byte-by-byte Description of file: SLICES -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 3 I3 --- slice Slice index 5- 9 F5.3 --- z [0.4/9.39] Slice center redshift 11-30 F20.18 --- b [0.0/0.13] Bandwidth scale used in the slice 32-51 F20.11 --- bg_dens [40365.86/43961969.29] Median density in the slice -------------------------------------------------------------------------------- Byte-by-byte Description of file: POINTS -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 3 I3 --- slice Slice index 5- 10 I6 --- id Source identifier 12- 29 F18.14 deg RA [149.66/150.58] Right Ascension 31- 48 F18.16 deg Dec [1.72/2.69] Declination 50- 67 F18.14 deg x [139.82/140.53] X coordinate in rotated frame 69- 86 F18.15 deg y [53.39/54.18] Y coordinate in rotated frame 88-107 F20.18 --- w [0.05/1.0] Weight used in density estimation 109-129 F21.19 deg adaptive_b [0.0/0.23] Adaptive bandwidth per object 131-148 F18.16 --- boundary_corr [0.99/3.79] Boundary correction factor -------------------------------------------------------------------------------- Byte-by-byte Description of file: OVERDENSITY -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 6 I6 --- id [3/780605] Source identifier (matches POINTS.id) 8-26 F19.14 deg RA [149.66/150.58]? Right Ascension 28-46 F19.16 deg Dec [1.72/2.69]? Declination 48-58 F11.8 --- density_excess Per-object overdensity 1 + delta -------------------------------------------------------------------------------- Acknowledgements: Hossein Hatamnia, hossein.hatamnia@email.ucr.edu ================================================================================ (prepared by author / pyreadme )