Measurements of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>B</mml:mi></mml:math>-mode polarization of the cosmic microwave background from 500 square degrees of SPTpol data
Bibliographic record
Abstract
We report a $B$-mode power spectrum measurement from the cosmic microwave background (CMB) polarization anisotropy observations made using the SPTpol instrument on the South Pole Telescope. This work uses $500\text{ }\text{ }{\mathrm{deg}}^{2}$ of SPTpol data, a five-fold increase over the last SPTpol $B$-mode release. As a result, the bandpower uncertainties have been reduced by more than a factor of two, and the measurement extends to lower multipoles: $52<\ensuremath{\ell}<2301$. Data from both 95 and 150 GHz are used, allowing for three cross-spectra: $95\text{ }\mathrm{GHz}\text{ }\ifmmode\times\else\texttimes\fi{}\text{ }95\text{ }\mathrm{GHz}$, $95\text{ }\mathrm{GHz}\text{ }\ifmmode\times\else\texttimes\fi{}\text{ }150\text{ }\mathrm{GHz}$, and $150\text{ }\mathrm{GHz}\text{ }\ifmmode\times\else\texttimes\fi{}\text{ }150\text{ }\mathrm{GHz}$. $B$-mode power is detected at very high significance; we find $P(BB<0)=5.8\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}71}$, corresponding to a $18.1\ensuremath{\sigma}$ detection of power. With a prior on the galactic dust from Planck, WMAP and BICEP2/Keck observations, the SPTpol $B$-mode data can be used to set an upper limit on the tensor-to-scalar ratio, $r<0.44$ at 95% confidence (the expected $1\ensuremath{\sigma}$ constraint on $r$ given the measurement uncertainties is 0.22). We find the measured $B$-mode power is consistent with the Planck best-fit $\mathrm{\ensuremath{\Lambda}}\mathrm{CDM}$ model predictions. Scaling the predicted lensing $B$-mode power in this model by a factor ${A}_{\mathrm{lens}}$, the data prefer ${A}_{\mathrm{lens}}=1.17\ifmmode\pm\else\textpm\fi{}0.13$. These data are currently the most precise measurements of $B$-mode power at $\ensuremath{\ell}>320$.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.006 | 0.004 |
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".