Kavli Affiliate: Mark Vogelsberger
| First 5 Authors: Nathan Jamieson, Aaron Smith, Meredith Neyer, Rahul Kannan, Enrico Garaldi
| Summary:
The growth of ionized hydrogen bubbles in the intergalactic medium around
early luminous objects is a fundamental process during the Epoch of
Reionization (EoR). In this study, we analyze bubble sizes and their evolution
using the state-of-the-art THESAN radiation-hydrodynamics simulation suite,
which self-consistently models radiation transport and realistic galaxy
formation throughout a large (95.5 cMpc)^3 volume of the Universe. Analogous to
the accretion and merger tree histories employed in galaxy formation
simulations, we characterize the growth and merger rates of ionized bubbles by
focusing on the spatially-resolved redshift of reionization. By tracing the
chronological expansion of bubbles, we partition the simulation volume and
construct a natural ionization history. We identify three distinct stages of
ionized bubble growth: (1) initial slow expansion around the earliest ionizing
sources seeding formation sites, (2) accelerated growth through percolation as
bubbles begin to merge, and (3) rapid expansion dominated by the largest
bubble. Notably, we find that the largest bubble emerges by z=9-10, well before
the midpoint of reionization. This bubble becomes dominant during the second
growth stage, and defines the third stage by rapidly expanding to eventually
encompass the remainder of the simulation volume and becoming one of the few
bubbles actively growing. Additionally, we observe a sharp decline in the
number of bubbles with radii around ~10 cMpc compared to smaller sizes,
indicating a characteristic scale in the final segmented bubble size
distribution. Overall, these chronologically sequenced spatial reconstructions
offer crucial insights into the physical mechanisms driving ionized bubble
growth during the EoR and provide a framework for interpreting the structure
and evolution of reionization itself.
| Search Query: ArXiv Query: search_query=au:”Mark Vogelsberger”&id_list=&start=0&max_results=3