Discovery of a Powerful >10<sup>61</sup> erg AGN Outburst in the Distant Galaxy Cluster SPT-CLJ0528-5300
Bibliographic record
Abstract
Abstract We present ∼103 ks of Chandra observations of the galaxy cluster SPT-CLJ0528-5300 (SPT0528, z = 0.768). This cluster harbors the most radio-loud (L 1.4GHz = 1.01 × 1033 erg s−1 Hz−1) central active galactic nucleus (AGN) of any cluster in the South Pole Telescope (SPT) Sunyaev–Zeldovich survey with available X-ray data. We find evidence of AGN-inflated cavities in the X-ray emission, which are consistent with the orientation of the jet direction revealed by Australia Telescope Compact Array radio data. The combined probability that two such depressions—each at ∼1.4–1.8σ significance, oriented ∼180° apart and aligned with the jet axis—would occur by chance is 0.1%. At ≳1061 erg, the outburst in SPT0528 is among the most energetic known in the universe, and certainly the most powerful known at z > 0.25. This work demonstrates that such powerful outbursts can be detected even in shallow X-ray exposures out to relatively high redshifts (z ∼ 0.8), providing an avenue for studying the evolution of extreme AGN feedback. The ratio of the cavity power ( P cav = ( 9.4 ± 5.8 ) × 10 45 erg s−1) to the cooling luminosity (L cool = (1.5 ± 0.5) × 1044 erg s−1) for SPT0528 is among the highest measured to date. If, in the future, additional systems are discovered at similar redshifts with equally high P cav/L cool ratios, it would imply that the feedback/cooling cycle was not as gentle at high redshifts as in the low-redshift universe.
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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 | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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 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".