Multi-epoch observations of extremely high-velocity emergent broad absorption
Bibliographic record
Abstract
We present the discovery of the highest velocity C iv broad absorption line to date in the z = 2.47 quasar SDSS J023011.28+005913.6, hereafter J0230. In comparing the public DR7 and DR9 spectra of J0230, we discovered an emerging broad absorption trough outflowing at ∼60 000 km s−1, which we refer to as trough A. In pursuing follow up observations of trough A, we discovered a second emergent C iv broad absorption trough outflowing at ∼40 000 km s−1, namely trough B. In total, we collected seven spectral epochs of J0230 that demonstrate emergent and rapidly (∼10 d in the rest-frame) varying broad absorption. We investigate two possible scenarios that could cause these rapid changes: bulk motion and ionization variability. Given our multi-epoch data, we were able to rule out some simple models of bulk motion, but have proposed two more realistic models to explain the variability of both troughs. Trough A is likely an augmented ‘crossing disc’ scenario with the absorber moving at 10 000 < v(km s−1) < 18 000. Trough B can be explained by a flow-tube feature travelling across the emitting region at 8000 < v(km s−1) < 56 000. If ionization variability is the cause for the changes observed, trough A's absorber has ne ≥ 724 cm−3 and is at requal ≥ 2.00 kpc, or is at r < 2.00 kpc with no constraint on the density; trough B's absorber either has ne ≥ 1540 cm−3 and is at requal ≥ 1.37 kpc, or is at r < 1.37 kpc with no constraint on the density.
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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".