Velocity shift of a C IV broad absorption line in quasar SDSS J145229.08+093204.9
Bibliographic record
Abstract
We present the observation of a velocity shift in the broad absorption line (BAL) of C IV ion in quasar SDSS J145229.08+093204.9 (hereafter J1452+0932).This quasar exhibits three distinct BAL systems, designated as systems A, B, and C. Notably, system A, which possesses the highest velocity of approximately −23 000 km s−1, demonstrates a velocity shift of −1097 km s−1 in its C IV ion over a rest-frame period of approximately 1.7 years. To elucidate the nature of these variations, we conducted a comprehensive analysis focusing on the variation situation, location, ionisation state, and profile shape of the three BAL systems in J1452+0932. Our findings reveal that system A is situated closer to the central source compared to systems B and C. Furthermore, system A exhibits higher velocities, higher ionisation states, and smoother profile morphologies. These characteristics collectively suggest that the outflow generating system A is situated in a particularly extreme environment and experiences more pronounced impacts from background radiation energy than systems B and C. Consequently, we postulate that the observed velocity shift in system A may signify an actual line-of-sight acceleration of the outflow, induced by the radiation pressure emanating from the central source. Specifically, this scenario could occur if our line of sight intersects an outflow at a location where it is undergoing acceleration towards its terminal outflow velocity, or if a previously coasting outflow is undergoing renewed acceleration.
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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 | 0.000 |
| 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".