Relative importance of compaction mechanisms

Determine the relative importance of gas-rich inflows, mergers, violent disk instabilities, and clump migration in driving rapid central compaction in massive galaxies.

Background

The paper describes compaction as a phase in which massive galaxies rapidly build dense stellar cores. Several dissipative mechanisms have been proposed, including gas-rich inflows, mergers, violent disk instabilities, and inward migration of stellar clumps, but their contributions are not observationally distinguished. Resolving their relative importance is necessary for identifying the physical origin of dense-core formation.

References

Compaction is thought to be driven by a variety of dissipative processes, including gas-rich inflows, mergers, violent disk instabilities, and clump migration, but their relative importance remains uncertain.

— Interplay of Compaction, Quenching, and Black Hole Growth in the Most Massive Galaxies since $z\sim5$: Insights from JWST and Chandra Data  (2608.24124 - Haryana et al., 25 Aug 2026) in Section 1, Introduction

However, because we do not directly measure gas inflow rates, the specific physical channel responsible for the rapid central buildup remains uncertain.

— Interplay of Compaction, Quenching, and Black Hole Growth in the Most Massive Galaxies since $z\sim5$: Insights from JWST and Chandra Data  (2608.24124 - Haryana et al., 25 Aug 2026) in Section 5.3, Comparison with Theoretical Expectations