Publication
Environmental Dependence of Galactic Properties Traced by Lyα Forest Absorption: Diversity among Galaxy Populations
Publisher:
American Astronomical Society
Date:
03-2021
DOI:
10.3847/1538-4357/ABD2AF
Abstract: In order to shed light on how galactic properties depend on the intergalactic medium (IGM) environment traced by the Ly α 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 ⊙ are the dominant contributor to the total CCF signal. We also investigate CCFs for several galaxy populations: Ly α emitters (LAEs), H α emitters (HAEs), [O iii ] emitters (O3Es), active galactic nuclei (AGNs), and submillimeter galaxies (SMGs), and we detect the highest signal in AGNs and SMGs at large scales ( r ≥ 5 h −1 Mpc), but in LAEs at small scales ( r 5 h −1 Mpc). We find that they live in various IGM environments—HAEs trace the IGM in a similar manner to the continuum-selected galaxies, but LAEs and O3Es tend to reside in higher-density regions. Additionally, LAEs’ CCF is flat up to r ∼ 3 h −1 Mpc, indicating that they tend to avoid the highest-density regions. For AGNs and SMGs, the CCF peak at r = 5−6 h −1 Mpc implies that they tend to be in locally lower-density regions. We suspect that it is due to the photoionization of IGM H i by AGNs, i.e., the proximity effect.