A consistent radio to sub-mm pc-scale study of the nucleus of NGC 1068
Bibliographic record
Abstract
ABSTRACT The origin of radio emission in radio-quiet (RQ) active galactic nucleus (AGN) remains a long-standing mystery. We present a detailed study of the cm to sub-mm emission from the nucleus of the nearby prototypical RQ Seyfert 2 galaxy, NGC 1068. We analyse observations between 4.5 and 706 GHz using e-MERLIN, VLA, and ALMA. We restricted all data used for imaging to a matching $uv-$range of 15–3300 k$\lambda$, to ensure that all data sampled the same spatial scales. All images were restored with a $\sim$0.06 arcsec beam. To derive the spectral energy distribution (SED), we fit synchrotron, free–free, dust, and coronal component models to these data. We report that the sub-mm excess between $\sim$200 and 700 GHz is consistent with synchrotron emission from a compact and optically thick corona with a radius $R_\mathrm{c}\approx 70\pm 5 \, R_\mathrm{g}$, a fraction of $\sim$$10\pm 2$ per cent of the energy density in the form of non-thermal electrons, and a magnetic field strength $B\approx 148$ G. The luminosity of the corona is roughly consistent with – though higher than – the expected from mm–X-ray correlations derived in recent studies of RQ AGNs. This difference is likely due to the corona SED peaking at ($\approx$550 GHz). Between 10 and $\sim$200 GHz, the SED is dominated by free–free emission. High angular resolution observations at frequencies below 5 GHz are needed to constrain a putative optically thin synchrotron component and the amount of free–free absorption.
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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) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| 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".