JWST + ALMA Dust Enshrouded Star-formation in the Spiderweb protocluster at the cosmic noon

The distribution of matter within the Universe is defined by a complex multi-scale inter-connected network of filaments known as the cosmic web, with galaxy clusters (i.e., exceedingly dense regions) residing at its nodes. In the early universe (z>2), young forming clusters are observed as strong overdensities of gas-rich dusty starburst galaxies, becoming for a short time the dominant contribution to the star formation rate density before rapidly transitioning towards the massive quiescent population that dominates mature clusters only a few Gyrs later. However, the accompanying large amounts of dust (a byproduct of star formation) heavily obscure such transformative processes, challenging optical observations even with the HST and preventing us from obtaining an unambiguous view of stellar mass growth in early dense environments. The JADES project will overcome such obstacles for the first time by disentangling the star-forming and dust components using deep and high-resolution observations in the rest-frame NIR and (sub-)millimeter regime traced by approved JWST and already available ALMA programs in the legacy Spiderweb protocluster field at z=2.16. In particular, JADES will be the first to establish a full census of star-formation activities (obscured and unobscured) by using the dust-free Paβ star formation indicator (JWST) across the large-scale structure of this protocluster. JADES will also trace the distribution of dust-obscured star-forming regions within previously identified Subaru Hα emitters by making use of their Paβ/Hα ratio (Balmer decrement), and it will map and weight the dust and molecular gas content within individual objects (ALMA) establishing a direct comparison between the star-forming and dusty regions. Altogether, JADES will transform this field into the benchmark of environmental studies, becoming the cornerstone of present and future numerical simulations investigating the formation of structure and mass build-up at this cosmic epoch.