Bibliographic record
Abstract
We investigate the relationship between quasars (QSOs) and close companion galaxies using photometry and spectroscopy from the large dataset of the SDSS DR16 survey. Using the SDSS-QSO catalogue of quasars, we selected objects with 0.1 < z ≤ 0.35 and absolute magnitude M ( r ) < − 21.3. For all these targets, we searched for candidate companion galaxies located at a projected distance from the target of < 700 kpc and a radial velocity difference from the QSO of Δ V < 1000 km/s. We find that in 447 QSOs at least one companion galaxy was found to be associated. A total of 691 associated galaxies were found in these QSO fields. In the majority there was just one associated galaxy however in several cases a number of companion were also discovered and in two cases the QSO was found in a rich galaxy environments. We note that the possible contamination attributed to a chance projection of the companion galaxies is less than 5%. Based on the available data we expected to find on average ∼2 associated companion galaxies for each QSO. A small fraction (13%) of the companion galaxies exhibit [OII] emission lines as signature of recent star formation. However a similar fraction (16%) of unassociated galaxies in the same QSO fields exhibit [OII] emission. Overall this study suggests that there is no significant link between the presence of these close companion galaxies or the signature of recent star formation and QSO nuclear activity.
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.000 | 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) | 0.003 | 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".