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.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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) | 0.000 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| 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".