<i>Euclid</i> : Early Release Observations – Interplay between dwarf galaxies and their globular clusters in the Perseus galaxy cluster
Bibliographic record
Abstract
We present an analysis of globular clusters (GCs) of dwarf galaxies in the Perseus galaxy cluster that explores the relationship between dwarf galaxy properties and their GCs. Our focus is on GC numbers ( N GC ) and GC half-number radii ( R GC ) around dwarf galaxies, and their relations with host galaxy stellar masses ( M * ), central surface brightnesses ( μ 0 ), and effective radii ( R e ). This work is unique due to its large sample size and the absence of pre-selection based on μ 0 and R GC for dwarf galaxies. Interestingly, we find that at a given stellar mass, R GC is almost independent of the host galaxy μ 0 and R e , while R GC / R e depends on μ 0 and R e . Lower surface brightness and diffuse dwarf galaxies show R GC / R e ≈ 1, while higher surface brightness and compact dwarf galaxies show R GC / R e ≈ 1.5–2. This means that for dwarf galaxies of similar stellar mass, the GCs have a similar median extent; however, their distribution is different from the field stars of their host. Additionally, low surface brightness and diffuse dwarf galaxies on average have a higher N GC than high surface brightness and compact dwarf galaxies at any given stellar mass. We also find that ultra-diffuse galaxies (UDGs) and non-UDGs in the sample have a similar R GC , while UDGs have a smaller R GC / R e (typically less than one) and a three to four times higher N GC than non-UDGs. Furthermore, when examining nucleated versus non-nucleated dwarf galaxies, we found that for M * > 10 8 M ⊙ , nucleated dwarf galaxies seem to have a smaller R GC and R GC / R e , with no significant differences seen between their N GC except at M * < 10 8 M ⊙ , where the nucleated dwarf galaxies tend to have a higher N GC . Lastly, we explored the stellar-to-halo mass ratio (SHMR) of dwarf galaxies (halo mass based on N GC ) and conclude that the Perseus cluster dwarf galaxies follow the expected SHMR at z = 0 extrapolated down to M * = 10 6 M ⊙ .
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".