TY - JOUR
T1 - Semi-analytic forecasts for JWST-IV. Implications for cosmic reionization and LyC escape fraction
AU - Aaron Yung, L. Y.
AU - Somerville, Rachel S.
AU - Finkelstein, Steven L.
AU - Popping, Gergö
AU - Davé, Romeel
AU - Venkatesan, Aparna
AU - Behroozi, Peter
AU - Ferguson, Harry C.
N1 - Publisher Copyright:
© 2020 The Author(s).
PY - 2020/8/1
Y1 - 2020/8/1
N2 - Galaxies forming in low-mass haloes are thought to be primarily responsible for reionizing the Universe during the first billion years after the big bang. Yet, these haloes are extremely inefficient at forming stars in the nearby Universe. In this work, we address this apparent tension, and ask whether a physically motivated model of galaxy formation that reproduces the observed abundance of faint galaxies in the nearby Universe is also consistent with available observational constraints on the reionization history. By interfacing the Santa Cruz semi-analytic model for galaxy formation with an analytic reionization model, we constructed a computationally efficient pipeline that connects 'ground-level' galaxy formation physics to 'top-level' cosmological-scale observables. Based on photometric properties of the galaxy populations predicted up to z = 15, we compute the reionization history of intergalactic hydrogen. We quantify the three degenerate quantities that influence the total ionizing photon budget, including the abundance of galaxies, the intrinsic production rate of ionizing photons, and the LyC escape fraction. We explore covariances between these quantities using a Markov chain Monte Carlo method. We find that our locally calibrated model is consistent with all currently available constraints on the reionization history, under reasonable assumptions about the LyC escape fraction. We quantify the fraction of ionizing photons produced by galaxies of different luminosities and find that the galaxies expected to be detected in James Webb Space Telescope Near-Infrared Camera (NIRCam) wide and deep surveys are responsible for producing ∼40-80 per cent of ionizing photons throughout the Epoch of Reionization. All results presented in this work are available at https://www.simonsfoundation.org/semi-analytic-forecasts-for-jwst/.
AB - Galaxies forming in low-mass haloes are thought to be primarily responsible for reionizing the Universe during the first billion years after the big bang. Yet, these haloes are extremely inefficient at forming stars in the nearby Universe. In this work, we address this apparent tension, and ask whether a physically motivated model of galaxy formation that reproduces the observed abundance of faint galaxies in the nearby Universe is also consistent with available observational constraints on the reionization history. By interfacing the Santa Cruz semi-analytic model for galaxy formation with an analytic reionization model, we constructed a computationally efficient pipeline that connects 'ground-level' galaxy formation physics to 'top-level' cosmological-scale observables. Based on photometric properties of the galaxy populations predicted up to z = 15, we compute the reionization history of intergalactic hydrogen. We quantify the three degenerate quantities that influence the total ionizing photon budget, including the abundance of galaxies, the intrinsic production rate of ionizing photons, and the LyC escape fraction. We explore covariances between these quantities using a Markov chain Monte Carlo method. We find that our locally calibrated model is consistent with all currently available constraints on the reionization history, under reasonable assumptions about the LyC escape fraction. We quantify the fraction of ionizing photons produced by galaxies of different luminosities and find that the galaxies expected to be detected in James Webb Space Telescope Near-Infrared Camera (NIRCam) wide and deep surveys are responsible for producing ∼40-80 per cent of ionizing photons throughout the Epoch of Reionization. All results presented in this work are available at https://www.simonsfoundation.org/semi-analytic-forecasts-for-jwst/.
KW - Cosmology: theory
KW - Dark ages, reioniza-tion, first stars
KW - Galaxies: evolution
KW - Galaxies: formation
KW - Galaxies: high-redshifts
KW - Galaxies: star formation
UR - http://www.scopus.com/inward/record.url?scp=85095451763&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85095451763&partnerID=8YFLogxK
U2 - 10.1093/mnras/staa1800
DO - 10.1093/mnras/staa1800
M3 - Article
AN - SCOPUS:85095451763
VL - 496
SP - 4574
EP - 4592
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
SN - 0035-8711
IS - 4
ER -