Revisiting the relation between the number of globular clusters and galaxy mass for low-mass galaxies
Abstract
Using a new method to estimate total galaxy mass (MT) and two samples of low-luminosity galaxies containing measurements of the number of globular clusters (GCs) per galaxy (NGC), we revisit the NGC-MT relation using a total of 203 galaxies, 157 of which have MT ≤ 1010 M⊙. We find that the relation is nearly linear, NGC ∝ MT0.92 ± 0.08 down to at least MT ~ 108.75 M⊙. Because the relationship extends to galaxies that average less than one GC per galaxy and to a mass range in which mergers are relatively rare, the relationship cannot be solely an emergent property of hierarchical galaxy formation. The character of the radial GC distribution in low-mass galaxies, and the lack of mergers at these galaxy masses, also appears to challenge models in which the GCs form in central, dissipatively concentrated high-density, high-pressure regions and are then scattered to large radius. The slight difference between the fitted power-law exponent and a value of one leaves room for a shallow MT-dependent variation in the mean mass per GC that would allow the relation between total mass in GCs and MT to be linear.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- June 2022
- DOI:
- 10.1093/mnras/stac1072
- arXiv:
- arXiv:2204.06529
- Bibcode:
- 2022MNRAS.513.2609Z
- Keywords:
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- globular clusters: general;
- galaxies: formation;
- galaxies: star clusters: general;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- Accepted for publication in MNRAS (6 pages, 3 figures)