The formation and disruption of globular cluster populations in simulations of present-day L* galaxies with controlled assembly histories

Newton, O ORCID: 0000-0002-2769-9507, Davies, JJ, Pfeffer, J ORCID: 0000-0003-3786-8818, Crain, RA ORCID: 0000-0001-6258-0344, Kruijssen, JMD ORCID: 0000-0002-8804-0212, Pontzen, A and Bastian, N (2025) The formation and disruption of globular cluster populations in simulations of present-day L* galaxies with controlled assembly histories. Monthly Notices of the Royal Astronomical Society. ISSN 0035-8711

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Abstract

Globular clusters (GCs) are sensitive tracers of galaxy assembly histories but interpreting the information they encode is challenging because mergers are thought to promote both the formation and disruption of GCs. We use simulations with controlled merger histories to examine the influence of merger mass ratio on the GC population of a present-day L* galaxy, using the genetic modification technique to adjust the initial conditions of a galaxy that experiences major mergers at z = 1.7 and z = 0.77 (organic case), so the later merger has twice its original mass ratio (enhanced case), or is prevented from occurring (suppressed case). We evolve the three realizations with E-MOSAICS, which couples sub-grid star cluster formation and evolution models to the EAGLE galaxy formation model. Relative to the organic case, the mass of surviving GCs is elevated (reduced) in the enhanced (suppressed) case, indicating that major mergers promote a net boost to the GC population. The boost is clearly quantified by the GC specific mass, SM, because it is sensitive to the number of the most massive GCs, whose long characteristic disruption timescales enable them to survive their hostile natal environments. In contrast, the specific frequency, TN, is insensitive to assembly history because it primarily traces low-mass GCs that tend to be disrupted soon after their formation. The promotion of GC formation and disruption by major mergers imprints a lasting and potentially observable signature: an elevated mass fraction of field stars in the galaxy’s stellar halo that were born in star clusters.

Item Type:	Article
Uncontrolled Keywords:	5109 Space Sciences; 5107 Particle and High Energy Physics; 5101 Astronomical Sciences; 51 Physical Sciences; 0201 Astronomical and Space Sciences; Astronomy & Astrophysics; 5101 Astronomical sciences; 5107 Particle and high energy physics; 5109 Space sciences
Subjects:	Q Science > QB Astronomy Q Science > QC Physics
Divisions:	Astrophysics Research Institute
Publisher:	Oxford University Press (OUP)
Date of acceptance:	15 July 2025
Date of first compliant Open Access:	6 August 2025
Date Deposited:	06 Aug 2025 12:53
Last Modified:	06 Aug 2025 13:00
DOI or ID number:	10.1093/mnras/staf1226
URI:	https://researchonline.ljmu.ac.uk/id/eprint/26903

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