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

Research output: Contribution to journalJournal articlepeer-review

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

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 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), [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 similar to 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
JournalAstrophysical Journal
Volume909
Issue number2
Number of pages21
ISSN0004-637X
DOIs
Publication statusPublished - 1 Mar 2021

    Research areas

  • Galaxy formation, Galaxy evolution, Ly alpha forest, Intergalactic medium, Large-scale structure of the universe, Ly alpha galaxies, Emission line galaxies, AGN host galaxies

Links

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