Environmental Dependence of Galactic Properties Traced by Ly$\alpha$ Forest Absorption: Diversity among Galaxy Populations

Understand

In order to shed light on how galactic properties depend on the intergalactic medium (IGM) environment traced by the Ly$\alpha$ forest, we observationally investigate the IGM-galaxy connection using the publicly available 3D IGM tomography data (CLAMATO) and several galaxy catalogs in the COSMOS field.

• We measure the cross-correlation function (CCF) for $570$ galaxies with spec-$z$ measurements and detect a correlation with the IGM up to $50$ $h^{-1}$ comoving Mpc.
• We show that galaxies with stellar masses of $10^9-10^{10}$ M$_\odot$ are the dominant contributor to the total CCF signal.
• We also investigate CCFs for several galaxy populations: Ly$\alpha$ emitters (LAEs), H$\alpha$ emitters (HAEs), [OIII] emitters (O3Es), active galactic nuclei (AGNs), and submillimeter galaxies (SMGs), and we detect the highest signal in AGNs and SMGs at large scales ($r\geq5$ $h^{-1}$ Mpc), but in LAEs at small scales ($r<5$ $h^{-1}$ Mpc).