Comprehensive view of a<i>z</i> ∼ 6.5 radio-loud quasi-stellar object: From the radio to the optical/NIR to the X-ray band
Bibliographic record
Abstract
We present a multi-wavelength analysis, from the radio to the X-ray band, of the redshiftz = 6.44 VIK J2318−31 radio-loud quasi-stellar object, one of the most distant currently known of this class. The work is based on newly obtained observations (uGMRT, ATCA, andChandra) as well as dedicated archival observations that have not yet been published (GNIRS and X-shooter). Based on the observed X-ray and radio emission, its relativistic jets are likely young and misaligned from our line of sight. Moreover, we can confirm, with simultaneous observations, the presence of a turnover in the radio spectrum atνpeak ∼ 650 MHz that is unlikely to be associated with self-synchrotron absorption. From the near-infrared spectrum we derived the mass of the central black hole, $ M_{\mathrm{BH}}=8.1^{+6.8}_{-5.6} \times 10^8\,{M_{\odot}} $, and the Eddington ratio, $ \lambda_{\mathrm{EDD}} = 0.8^{+0.8}_{-0.6} $, using broad emission lines as well as an accretion disc model fit to the continuum emission. Given the high accretion rate, the presence of a ∼8 × 108 M⊙black hole atz = 6.44 can be explained by a seed black hole (∼104 M⊙) that formed atz ∼ 25, assuming a radiative efficiencyηd ∼ 0.1. However, by assumingηd ∼ 0.3, as expected for jetted systems, the mass observed would challenge current theoretical models of black hole formation.
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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 | 0.003 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| 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".