Environmental dependence of galactic properties traced by Lyα forest absorption: Diversity among galaxy populations

Rieko Momose*, Kazuhiro Shimasaku, Nobunari Kashikawa, Kentaro Nagamine, Ikkoh Shimizu, Kimihiko Nakajima, Yasunori Terao, Haruka Kusakabe, Makoto Ando, Kentaro Motohara, Lee Spitler

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    21 Citations (Scopus)
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    In order to shed light on how galactic properties depend on the intergalactic medium (IGM) environment traced by the Lyα 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 109-1010 M are the dominant contributor to the total CCF signal. We also investigate CCFs for several galaxy populations: Lyα emitters (LAEs), Hα 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 ≥ 5h-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.

    Original languageEnglish
    Article number117
    Pages (from-to)1-21
    Number of pages21
    JournalAstrophysical Journal
    Issue number2
    Publication statusPublished - 10 Mar 2021

    Bibliographical note

    Copyright © 2021 The American Astronomical Society. First published in the Astrophysical Journal, 909(2), 117, 2021, published by IOP Publishing. The original publication is available at https://doi.org/10.3847/1538-4357/abd2af. Version archived for private and non-commercial use with the permission of the author/s and according to publisher conditions. For further rights please contact the publisher.


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