Bound Domains

TL;DR

This paper advocates for a bound-domain approach to better understand the energy required to unbind baryons from cosmic structures, challenging traditional halo models and offering new research directions.

Contribution

It introduces the concept of bound domains as a more accurate framework for studying baryon unbinding and discusses its potential to resolve open questions in galaxy cluster baryon distributions.

Findings

Bound domains remain gravitationally bound over cosmic time.

Potential wells of bound domains are similar ~1 Gyr after the Big Bang and today.

Future research can leverage bound domains to improve understanding of baryon distributions.

Abstract

How much energy is required to unbind baryons from the cosmological structures that originally bind them? This tutorial article explains why trying to answer this question using just a halo model can be misleading. Instead, it recommends parsing the universe into ``bound domains,'' which are the gravitationally bound structures that ultimately become widely separated islands as the universe evolves. It explains why a bound domain's potential well was about as deep ~1 Gyr after the Big Bang as it is now, and it outlines how future research might take advantage of a bound-domain approach to make progress on some open questions about the baryon distributions in and around galaxy groups and clusters.