The role of galaxies and AGN in reionizing the IGM - III. IGM-galaxy cross-correlations at z ~ 6 from eight quasar fields with DEIMOS and MUSE

Romain A. Meyer, Koki Kakiichi, Sarah E.I. Bosman, Richard S. Ellis, Nicolas Laporte, Brant E. Robertson, Emma V. Ryan-Weber, Ken Mawatari, Adi Zitrin

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

We present improved results of the measurement of the correlation between galaxies and the intergalactic medium transmission at the end of reionization. We have gathered a sample of 13 spectroscopically confirmed Lyman-break galaxies (LBGs) and 21 Lyman-α emitters (LAEs) at angular separations 20 arcsec ≤ θ ≤ 10 arcmin (~0.1-4 pMpc at z ~ 6) from the sightlines to eight background z ≥ 6 quasars. We report for the first time the detection of an excess of Lyman-α transmission spikes at ~10-60 cMpc from LAEs (3.2σ) and LBGs (1.9σ).We interpret the datawith an improvedmodel of the galaxy-Lyman-α transmission and two-point cross-correlations, which includes the enhanced photoionization due to clustered faint sources, enhanced gas densities around the central bright objects and spatial variations of the mean free path. The observed LAE(LBG)-Lyman-α transmission spike two-point cross-correlation function (2PCCF) constrains the luminosity-averaged escape fraction of all galaxies contributing to reionization to (fesc)MUV<-12 = 0.14+0.28-0.05 (0.23+0.46 -0.12). We investigate if the 2PCCF measurement can determine whether bright or faint galaxies are the dominant contributors to reionization. Our results show that a contribution from faint galaxies (MUV > -20 (2σ)) is necessary to reproduce the observed 2PCCF and that reionizationmight be driven by different sub-populations around LBGs and LAEs at z ~ 6.

Original languageEnglish (US)
Pages (from-to)1560-1578
Number of pages19
JournalMonthly Notices of the Royal Astronomical Society
Volume494
Issue number2
DOIs
StatePublished - 2020

Keywords

  • Dark ages
  • First stars
  • Galaxies: evolution
  • Galaxies: high-redshift
  • Intergalactic medium
  • Quasars: absorption lines
  • Reionization

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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