Lunch talk on Dec. 26, 2022

Two extremely massive galaxy protoclusters at z=2.24

Speaker:Dongdong Shi (PMO)

Venue:Video Conference

Time:12:30 PM, Monday, Dec. 26, 2022

Abstract:

Galaxy clusters are the largest gravitationally bound systems in the universe. Their progenitors, protoclusters, are predicted to have significant, large-scale overdensities of galaxy, allowing us to constrain the models of structure formation. In this talk, I will introduce two extremely massive protoclusters at z=2.24, BOSS1244 and BOSS1542, traced by a group of strong Lyα absorbers and identified as overdensities of narrowband-selected Hα emitters. Ground-based NIR spectroscopic observations have revealed that they have multiple kinematic components. They are the most overdense galaxy protoclusters (δg > 20) discovered to date at z > 2, and are expected to eventually evolve into the Coma-type galaxy clusters. The different morphologies they exhibit imply that they may be in different assembly stages in the formation of early galaxy clusters. Submillimeter observations with JCMT/SCUBA-2 at 850 μm reveal that submillimeter galaxies (SMGs) were located in the outskirt region and showed a prominent offset from the density peak of HAEs, implying the occurrence of violent star formation enhancement in the outskirts of HAE density peak. Finally, I will discuss the physical properties of protocluster member galaxies.

Report PPT:SWIFAR_Dongdong Shi.pdf