GALAXY PROPERTIES AND UV ESCAPE FRACTIONS DURING THE EPOCH OF REIONIZATION: RESULTS FROM THE RENAISSANCE SIMULATIONS

By Haoting Xu, John H. Wise, M. Norman, K. Ahn, Brian W. O'Shea. 2016

158 citations recorded by the source corpus.

Cosmic reionization is thought to be primarily fueled by the first generations of galaxies. We examine their stellar and gaseous properties, focusing on the star formation rates and the escape of ionizing photons, as a function of halo mass, redshift, and environment using the full suite of the Renaissance Simulations with an eye to provide better inputs to global reionization simulations. This suite probes overdense, average, and underdense regions of the universe of several hundred comoving Mpc3, each yielding a sample of over 3000 halos in the mass range of 107–109.5 at their final redshifts of 15, 12.5, and 8, respectively. In the process, we simulate the effects of radiative and supernova feedback from 5000 to 10,000 Population III stars in each simulation. We find that halos as small as 107 are able to host bursty star formation due to metal-line cooling from earlier enrichment by massive Population III stars. Using our large sample, we find that the galaxy-halo occupation fraction drops from unity at virial masses above 108.5 to ∼50% at 108 and ∼10% at 107 , quite independent of redshift and region. Their average ionizing escape fraction is ∼5% in the mass range of 108–109 and increases with decreasing halo mass below this range, reaching 40%–60% at 107 . Interestingly, we find that the escape fraction varies between 10%–20% in halos with virial masses of ∼3 × 109 . Taken together, our results confirm the importance of the smallest galaxies as sources of ionizing radiation contributing to the reionization of the universe.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/df076fbf46ca671feb5014c62411e144fc1b54b5

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Citations in the corpus

Charting the parameter space of the global 21-cm signal (2016, background): “Simulations of high-redshift stellar activity present a large scatter of values for SFE, especially for small halos which likely dominated the early Universe (e.g., Wise et al. 2014; O’Shea et al. 2015; Xu et al. 2016).”
Feedback-regulated star formation and escape of LyC photons from mini-haloes during reionization (2016, methodology): “We then adopt the formation rate of Pop III from the large volume simulations of Xu et al. (2016) (the “Normal” run) by using the fit, log ṀpopIII/(M yr −1 Mpc−3) = −6.428 + 0.275 z− 0.011z2.”
The SPHINX Cosmological Simulations of the First Billion Years: the Impact of Binary Stars on Reionization★ (2018, background): “…by using the predicted escape of photons from the high-resolution zooms as inputs for the unresolved escape of photons from galaxies in full reionization simulations, allowing predictions to be made for the contributions of different galaxy masses to reionization (Xu et al. 2016; Chen et al. 2017).”
Inferring the astrophysics of reionization and cosmic dawn from galaxy luminosity functions and the 21-cm signal (2018, background): “…likely to be negative, as SNe can more easily evacuate low column density channels from shallower DM potentials; the escape of ionizing photons is though to be determined by the covering fraction of these low column density channels (e.g. Paardekooper et al. 2015; Xu et al. 2016; Katz et al. 2018).”
A case study of hurdle and generalized additive models in astronomy: the escape of ionizing radiation (2018, background): “With fesc increasing with decreasing halo mass below M200 109 M , stressing the role of the smallest galaxies as sources of ionizing radiation (e.g. Xu et al. 2016).”