Oral Presentation
Clash of Titans: the impact of dense environment on massive dusty star-forming galaxies
Presenter: Yu-Jan Wang (ASIAA)
In recent years, understanding the impact of environment on galaxies within the local universe has been a focal point of research. However, during the 'cosmic noon' epoch (z = 2-4), it remains unclear how environmental factors influence galaxies and their characteristics. To address this, we investigate proto-clusters, the predecessors of local massive galaxy clusters. Building upon previous research efforts, we have identified environments hosting strong Lyman-alpha nebulae (referred to as enormous Lyman-alpha nebulae, ELANe) associated with quasars (QSOs) as potential proto-clusters. We conducted a number density analysis of dusty star-forming galaxies (DSFGs) around ELANe using JCMT/SCUBA-2 observations at 850 microns. We found the number of DSFGs around ELANe to be 2-3 times higher than those in blank fields. Further observations with ALMA detected 15 reliable CO emission lines in DSFGs around ELANe, and spectral energy distribution (SED) fitting using multi-wavelength data provided CO and infrared luminosity measurements. Comparing molecular and dust properties between ELANe and field samples, we found that gas fractions in DSFGs around ELANe on megaparsec scales were comparable to those in blank fields. Interestingly, gas fractions in DSFGs around QSOs at halo-scale distances showed a decrease similar to those observed in QSOs themselves. Overall, our findings suggest that only on the halo scales environmental factors significantly influence the interstellar medium properties of massive dusty star-forming galaxies.
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