A 31 GHz SURVEY OF LOW-FREQUENCY SELECTED RADIO SOURCES
Bibliographic record
Abstract
The 100 m Robert C. Byrd Green Bank Telescope and the 40 m Owens Valley Radio Observatory telescope have been used to conduct a 31 GHz survey of 3165 known extragalactic radio sources over 143 deg^2 of the sky. Target sources were selected from the NRAO VLA Sky Survey in fields observed by the Cosmic Background Imager (CBI); most are extragalactic active galactic nuclei (AGNs) with 1.4 GHz flux densities of 3-10 mJy. The resulting 31 GHz catalogs are presented in full online. Using a maximum-likelihood analysis to obtain an unbiased estimate of the distribution of the 1.4-31 GHz spectral indices of these sources, we find a mean 31-1.4 GHz flux ratio of 0.110 ± 0.003 corresponding to a spectral index of α = –0.71 ± 0.01 (S_ν ∝ ν^α); 9.0% ± 0.8% of sources have α > –0.5 and 1.2% ± 0.2% have α > 0. By combining this spectral-index distribution with 1.4 GHz source counts, we predict 31 GHz source counts in the range 1 mJy < S_(31) < 4 mJy, N(>S_(31)) = (16.7 ± 1.7) deg^(-2)(S_(31)/1 mJy)^(–0.80±0.07). We also assess the contribution of mJy-level (S_(1.4 GHz) < 3.4 mJy) radio sources to the 31 GHz cosmic microwave background power spectrum, finding a mean power of ℓ(ℓ + 1)C^(src)_ℓ /(2π) = 44 ± 14 μK^2 and a 95% upper limit of 80 μK^2 at ℓ = 2500. Including an estimated contribution of 12 μK^2 from the population of sources responsible for the turn-up in counts below S_(1.4 GHz) = 1 mJy, this amounts to 21% ± 7% of what is needed to explain the CBI high-ℓ excess signal, 275 ± 63 μK^2. These results are consistent with other measurements of the 31 GHz point-source foreground.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 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 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
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".