Cosmology with the galaxy bispectrum multipoles: Optimal estimation and application to BOSS data
Bibliographic record
Abstract
We present a framework for self-consistent cosmological analyses of the full-shape anisotropic bispectrum, including the quadrupole ($\ensuremath{\ell}=2$) and hexadecapole ($\ensuremath{\ell}=4$) moments. This features a novel window-free algorithm for extracting the latter quantities from data, derived using a maximum-likelihood prescription. Furthermore, we introduce a theoretical model for the bispectrum multipoles (which does not introduce new free parameters), and test both aspects of the pipeline on several high-fidelity mocks, including the PT Challenge suite of gigantic cumulative volume. This establishes that the systematic error is significantly below the statistical threshold, both for the measurement and modeling. As a realistic example, we extract the large-scale bispectrum multipoles from BOSS DR12 and analyze them in combination with the power spectrum data. Assuming a minimal $\mathrm{\ensuremath{\Lambda}}\mathrm{CDM}$ model, with a BBN prior on the baryon density and a Planck prior on ${n}_{s}$, we can extract the remaining cosmological parameters directly from the clustering data. The inclusion of the unwindowed higher-order ($\ensuremath{\ell}>0$) large-scale bispectrum multipoles is found to moderately improve one-dimensional cosmological parameter posteriors (at the 5%--10% level), though these multipoles are detected only in three out of four BOSS data segments at $\ensuremath{\approx}5\ensuremath{\sigma}$. Combining information from the power spectrum and bispectrum multipoles, the real space power spectrum, and the postreconstructed BAO data, we find ${H}_{0}=68.2\ifmmode\pm\else\textpm\fi{}0.8\text{ }\text{ }\mathrm{km}\text{ }{\mathrm{s}}^{\ensuremath{-}1}\text{ }{\mathrm{Mpc}}^{\ensuremath{-}1}$, ${\mathrm{\ensuremath{\Omega}}}_{m}=0.33\ifmmode\pm\else\textpm\fi{}0.01$ and ${\ensuremath{\sigma}}_{8}=0.736\ifmmode\pm\else\textpm\fi{}0.033$ (the tightest yet found in perturbative full-shape analyses). Our estimate of the growth parameter ${S}_{8}=0.77\ifmmode\pm\else\textpm\fi{}0.04$ agrees with both weak lensing and CMB results. The estimators and data used in this work have been made publicly available.
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 distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 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 teacher head, 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".