Poster Presentation
The search for protoclusters around quasar pairs: From Mpc-scale galaxy overdensities to kpc-scale gas accretion
Presenter: Eileen Herwig (Max Planck Institute for Astrophysics (MPA), Garching near Munich)
A commonly employed technique to identify protoclusters in the young universe is the search for overdensities of galaxies around high-mass halos, such as quasars or radio galaxies. Physically associated quasar pairs, two massive halos within a few hundred kiloparsecs of each other, are therefore predicted to be even more powerful tracers of the densest structures in the universe. On top of that, high-z quasars are usually associated with extended Lya emission on scales up to their virial radius, allowing for the direct study of cool gas accreted from the cosmic web into their circumgalactic medium.
In this contribution, I will report on our survey targeting nine quasar pairs at z~3 with JCMT/SCUBA-2 to reveal submillimeter galaxies (SMGs) in an area of approximately 32 Mpc^2. We find significantly higher overdensity factors compared to single quasar fields observed with a similar strategy, and the derived star formation rates are more centrally peaked, with star formation rate densities consistent with expectations for protocluster regions from simulations and observations.
To evaluate how these probable protocluster regions and their cores are fed through filamentary accretion of cool gas, I will discuss the alignment of SMGs with respect to the quasar pair direction as well as the alignment of extended Lya emission revealed in VLT/MUSE IFU data of eight quasar pairs.
I will further highlight the connection between central AGN number and SMG overdensity by reporting on the discovery of a quadruple AGN candidate in the center of the richest field in SCUBA-2 data.
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