No rungs attached: A distance-ladder-free determination of the Hubble constant through type II supernova spectral modelling
Bibliographic record
Abstract
Context. The ongoing discrepancy among Hubble constant (H0) estimates obtained through local distance ladder methods and early Universe observations poses a significant challenge to the ΛCDM model, suggesting potential new physics. Type II supernovae (SNe II) offer a promising technique for determining H0 in the Local Universe independently of the traditional distance ladder approach, opening up a complimentary path for testing this discrepancy. Aims. We aim to provide the first H0 estimate using the tailored expanding photosphere method (EPM) applied to SNe II, made possible by recent advancements in spectral modelling that enhance its precision and efficiency. Methods. Our tailored EPM measurement utilises a spectral emulator to interpolate between radiative transfer models calculated with TARDIS, allowing us to fit SN spectra efficiently and derive self-consistent values for luminosity-related parameters. We applied the method to a set of public data for ten SNe II at redshifts between 0.01 and 0.04. Results. Our analysis demonstrates that the tailored EPM allows us to obtain H0 measurements with a precision comparable to the most competitive established techniques, even when applied to literature data that are not designed for cosmological applications. We find an independent H0 value of 74.9 ± 1.9 (stat) km s−1 Mpc−1, which is consistent with most current local measurements. Considering dominant sources of systematic effects, we conclude that our systematic uncertainty is comparable to (or less than) the current statistical uncertainty. Conclusions. This proof-of-principle study highlights the potential of the tailored EPM as a robust and precise tool for investigating the Hubble tension independently of the local distance ladder. Observations of SNe II tailored to H0 estimations could make this an even more powerful tool by improving the precision and allowing us to improve our understanding of the systematic uncertainties and how to control them.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".