Using Artificial Neural Networks to Constrain the Halo Baryon Fraction during Reionization

Abstract

Radiative feedback from stars and galaxies has been proposed as a potential solution to many of the tensions with simplistic galaxy formation models based on $\Lambda$CDM, such as the faint end of the UV luminosity function. The total energy budget of radiation could exceed that of galactic winds and supernovae combined, which has driven the development of sophisticated algorithms that evolve both the radiation field and the hydrodynamical response of gas simultaneously, in a cosmological context. We probe self-feedback on galactic scales using the adaptive mesh refinement, radiative transfer, hydrodynamics, and $N$-body code. Unlike previous studies which assume a homogeneous UV background, we self-consistently evolve both the radiation field and gas to constrain the halo baryon fraction during cosmic reionization. We demonstrate that the characteristic halo mass with mean baryon fraction half the cosmic mean, $M_{\mathrm{c}}(z)$, shows very little variation as a function of mass-weighted ionization fraction. Furthermore, we find that the inclusion of metal cooling and the ability to resolve scales small enough for self-shielding to become efficient leads to a significant drop in $M_{\mathrm{c}}$ when compared to recent studies. Finally, we develop an Artificial Neural Network that is capable of predicting the baryon fraction of haloes based on recent tidal interactions, gas temperature, and mass-weighted ionization fraction. Such a model can be applied to any reionization history, and trivially incorporated into semi-analytical models of galaxy formation.

24 pages, 16 figures. Submitted to MNRAS

References in corpus (21)

• Cosmic Reionization and Early Star-Forming Galaxies: A Joint Analysis of New Constraints from Planck and Hubble Space Telescope
• Ubiquitous outflows in DEEP2 spectra of star-forming galaxies at z=1.4
• Massloss of galaxies due to a UV-background
• Model-independent evidence in favor of an end to reionization by z~6
• The effect of massive binaries on stellar populations and supernova progenitors
• Efficient Simulations of Early Structure Formation and Reionization
• Escape fraction of ionizing photons during reionization: effects due to supernova feedback and runaway OB stars
• The morphology of HII regions during reionization
• On the onset of galactic winds in quiescent star forming galaxies
• Ionized gas outflows and global kinematics of low-z luminous star forming galaxies
• Simulating Cosmic Reionization at Large Scales II: the 21-cm Emission Features and Statistical Signals
• Inside-out or Outside-in: The topology of reionization in the photon-starved regime suggested by Lyman-alpha forest data
• Self-regulated reionization
• Minihalo photoevaporation during cosmic reionization: evaporation times and photon consumption rates
• A radiative transfer scheme for cosmological reionization based on a local Eddington tensor
• Galaxies that Shine: radiation-hydrodynamical simulations of disk galaxies
• Photo-heating and supernova feedback amplify each other's effect on the cosmic star formation rate
• Probing the Neutral Fraction of the IGM with GRBs during the Epoch of Reionization
• Quasar H II Regions During Cosmic Reionization
• Dependence of the Local Reionization History on Halo Mass and Environment: Did Virgo Reionize the Local Group?
• The reionization of galactic satellite populations

Cited by in corpus (6)

• Measuring the topology of reionization with Betti numbers
• A machine learning approach to mapping baryons onto dark matter haloes using the EAGLE and C-EAGLE simulations
• Deep learning approach for identification of HII regions during reionization in 21-cm observations
• Identifying MgII Narrow Absorption Lines with Deep Learning
• Stellar populations and origin of thick disks in AURIGA simulations
• MAHGIC: A Model Adapter for the Halo-Galaxy Inter-Connection