WP-1  Protoclusters

• How much star formation density they host?   

Due to observational constraints, most of the follow-up studies are limited to the central  few square arminutes area allowed by the 8m-class telescopes instruments' field of view. The more robust IR/radio SFR tracers available are usually too shallow to into the normal "main-sequence" massive galaxy population. We have obtained deep MeerKAT in the Spideerweb field to use the radio continuum as a proxy for dust-unbiased star formation and get accurate measurements of the protocluster star formation content. First results (Pannella et al. in preparation) seem to suggest that protocluster galaxies host more star-formation (and likely more molecular gas) than their field analogous  

• How extended are they in physical scales?   

Proto-clusters are expected to extend over tens of Mpc scales, small-field observations dramatically limit our investigation and understanding of these systems. We have acquired and reduced, in the field of the Spiderweb, an optical-NIR database extending over the tens of arcmin scales, complementing the new MeerKAT  and the FIR Herschel data, in order to obtain a detailed picture of the extended large scale structure around the central structure and directly witness the mass assembly of this specific structure (Pannella et al. in preparation).