Erratum: “A Multimass Velocity Dispersion Model of 47 Tucanae Indicates No Evidence for an Intermediate-mass Black Hole” (2019, ApJ, 875, 1)
Bibliographic record
Abstract
A simple, but non-trivial error has been discovered in the analysis of Mann et al. (2019).The nature of the error was a multiplicative factor in the portion of the analysis code that converts between the dimensionless units used for internal calculations and the physically meaningful units (i.e., solar masses and arcseconds) displayed as results.The erroneous factor was related to the size of the distribution in question (i.e., its a parameter).The overall effect was that the stellar remnant and binary population masses, being more tightly distributed, were being disproportionately inflated.We also note an unrelated typo in Table 2, where the reported binary fractions ( f ) were too small by a factor of 10, has also been identified and corrected.In this case, the error was merely typographic and had no effect on the results.The analysis has been re-run with a corrected unit conversion process.The affected Tables 2 and 3 and Figures 5678have been recreated and are presented here with their original numberings.The figures and tables have been reproduced with the same retention fraction (8.5%) of stellar-mass black holes (sBHs) and neutron stars (NSs) as was used in the initial publication in order to facilitate comparison.However, this value no longer holds particular significance.Our results are affected as follows.Overall, the concentrated populations of binaries and stellar remnants do not contribute as strongly to the central velocity dispersion as previously determined.The trend between the fitted intermediate-mass black hole (IMBH) mass and the choice of the retention fraction is qualitatively similar, but the strength is much diminished.Thus, the constraint we placed on the sBH and NS retention of 8.5% in the original publication must be relaxed.Additionally, the results of) are now consistent with a retention fraction of ∼25% by the new analysis.The predicted IMBH mass does not drop to zero until the retention fraction approaches 100%, indicating the sBH population cannot fully account for the central velocity dispersion rise unless one can justify a nearly total retention of the inferred population.The parameter values reported at the beginning of the original Section 4.1 for a 8.5% retention model should be replaced with: M IMBH =4400±1900 M e , M Cl =(1.177±0.017)×106 M e , a Cl =41 1±1 2, and an M IMBH /M Cl ratio of 0.37%±0.16%.
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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 | 0.001 | 0.008 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.006 | 0.001 |
| Scholarly communication | 0.002 | 0.002 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.003 | 0.005 |
| Insufficient payload (model declined to judge) | 0.046 | 0.021 |
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".