Oral Presentation

Testing Web Feeding Model for Star Formation in Galaxy Clusters in the COSMOS Field

Author(s): Eunhee Ko(SNU), Myungshin Im(SNU) et al.

Presenter: Eunhee Ko (Seoul National University)

It is yet to be understood what controls the star formation activity in high-redshift galaxy clusters. One recently proposed mechanism is that the star formation activity in galaxy clusters is fed by cold gas and star-forming galaxies in large-scale structures surrounding them, which we call the “web feeding model”. Using galaxies in the COSMOS2020 catalog, with mass completeness at log(M/M⊙) ≥ 8.78 and reliable photometric redshift dataσ δz/(1+z)≈0.01, we study the star formation activities of galaxy clusters and their surrounding environment to test the web feeding model. We first identify the 76 overdense regions at 0.1≤z≤1.4 with number density exceeding the 4σ-level from photometric redshift data as galaxy clusters. Furthermore, we identify galaxy large-scale structures and present the anti-correlation between quiescent galaxy fraction, an indicator of star-forming activity, and the prevalence of galaxy large-scale structures. We propose that variation of quiescent galaxy fraction at∼1 can be explained by the web feeding model.