Environments around Quasars at z ∼ 3 Revealed by Wide-field Imaging with Subaru HSC and CFHT
Bibliographic record
Abstract
Abstract We examine the local density environments around 67 quasars at z ∼ 3 by combining the imaging data of Hyper Suprime-Cam Subaru Strategic Program and Canada–France–Hawaii Telescope Large Area U-band Deep Survey over about 20 deg2. Our measurements exploit U-dropout galaxies in the vicinities of quasars taken from the Sloan Digital Sky Survey. We find that the quasars have an indistinguishable surrounding density distribution from the U-dropout galaxies and that three quasars are associated with protocluster candidates within a projected separation of 3′. According to a halo evolutionary model, our results suggest that quasars at this epoch occupy haloes with a typical mass of 1.3 − 0.9 + 1.4 × 10 13 h − 1 M ⊙ . We also investigate the dependence of the local galaxy overdensity on ultraviolet (UV) luminosities, black hole masses, and proximity zone sizes of the quasars, but no statistically significant correlation was found. Finally, we find that the local density of faint U-dropout galaxies are lower than that of bright U-dropout galaxies within a projected distance of 0.51 ± 0.05 physical Mpc, where the quasar UV radiation is 30 times more intense than background UV radiation. We argue that photoevaporation may suppress galaxy formation at short distances where the quasar UV intensity is strong, even in massive haloes.
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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 | 0.002 | 0.001 |
| 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".