Jets blowing bubbles in the young radio galaxy 4C 31.04
Bibliographic record
Abstract
We report the discovery of shocked molecular and ionized gas resulting from jet-driven feedback in the low-redshift (z = 0.0602) compact radio galaxy 4C 31.04 using near-IR imaging spectroscopy. 4C 31.04 is a ∼100 pc double-lobed Compact Steep Spectrum source believed to be a very young active galactic nucleus (AGN). It is hosted by a giant elliptical with a |${\sim } 10^{9}\, \rm M_\odot$| multiphase gaseous circumnuclear disc. We used high spatial resolution, adaptive optics-assisted H- and K-band integral field Gemini/NIFS observations to probe (1) the warm (∼103 K) molecular gas phase, traced by ro-vibrational transitions of H2, and (2), the warm ionized medium, traced by the [Fe ii]|$_{1.644\, \rm \mu m}$| line. The [Fe ii] emission traces shocked gas ejected from the disc plane by a jet-blown bubble |$300\!-\!400\, \rm pc$| in diameter, while the H2 emission traces shock-excited molecular gas in the interior |${\sim } 1\, \rm kpc$| of the circumnuclear disc. Hydrodynamical modelling shows that the apparent discrepancy between the extent of the shocked gas and the radio emission can occur when the brightest regions of the synchrotron-emitting plasma are temporarily halted by dense clumps, while less bright plasma can percolate through the porous ISM and form an energy-driven bubble that expands freely out of the disc plane. Simulations suggest that this bubble is filled with low surface brightness plasma not visible in existing VLBI observations of 4C 31.04 due to insufficient sensitivity. Additional radial flows of jet plasma may percolate to ∼ kpc radii in the circumnuclear disc, driving shocks and accelerating clouds of gas, giving rise to the H2 emission.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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 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".