ADF22-WEB: Massive galaxy formation shaped by cosmic web filaments in the z = 3.1 proto-cluster core

Abstract

We present a census of dust, molecular gas, and galaxy structure in 18 dusty star-forming galaxies (DSFGs) at $z=3.09$ embedded in Ly$\alpha$-traced cosmic web filaments in the core of the SSA22 proto-cluster, using multi-band ALMA, JWST imaging, and JVLA CO(1--0). Using up to six ALMA bands and Herschel/SPIRE data, we construct rest-frame far-infrared spectral energy distributions. The DSFGs span two orders of magnitude in far-infrared luminosity ($L_{\mathrm{FIR}}\sim 10^{11}$--$10^{13}{L}_{\odot }$), with median values of $\log (L_{\mathrm{FIR}}/L_{\odot })=11.56_{-0.37}^{+0.32}$ and $T_{\mathrm{dust}}=25_{-3}^{+6}\mathrm{K}$. For eight DSFGs with high-resolution ($\sim 1$ kpc) JWST and ALMA imaging, we measure stellar and dust surface densities and find a positive correlation, suggesting that structural compaction of the stellar component proceeds together with that of the interstellar medium. We report 12 detections of CO(1--0), 18 of CO(3--2), four each of CO(8--7) and CO(9--8), and one of CO(12--11). The median brightness temperature ratio between CO(3--2) and CO(1--0) is $r_{31}=0.66_{-0.04}^{+0.05}$, consistent with field galaxies at similar redshifts. The high-$J$ CO lines show relatively low excitation, and the CO(8--7)/CO(3--2) ratio correlates with star-formation rate surface density, suggesting that molecular gas excitation is primarily regulated by star formation. Lower-mass galaxies show excess molecular gas fractions and depletion times relative to field scaling relations. By combining quiescent galaxy samples in the same field, we identify a sequence from gas-rich systems with low stellar surface density to gas-poor, compact systems with high stellar surface density. These results suggest that massive galaxy evolution in dense environments is governed by a baryon cycle linking gas supply, star formation, and structural transformation within the cosmic web environment.

Accepted for publication in PASJ