Discovery of a [CLC]z[/CLC] = 0.77 Galaxy Cluster with Multiple, Bright, Strong-Lensing Arcs
Bibliographic record
Abstract
We report the discovery of a remarkable strong-lensing cluster from the ongoing Red-Sequence Cluster Survey (RCS). RCS 0224-0002, at a spectroscopic redshift of 0.773, lenses two to four separate background sources. These arcs are of relatively high surface brightness and hence amenable to detailed follow-up study. We provide preliminary photometry and spectroscopy of RCS 0224-0002 and discuss in detail the one lensed source for which a redshift has so far been determined. This galaxy, at a redshift of 4.8786, appears to be composed of a star-forming core enveloped in a Lyα emitting cloud. Moreover, it shows no measurable velocity structure to a limit of ∼50 km s-1 over a region likely to be ∼1 kpc in size. The available data are also used to develop an initial lensing model, which shows RCS 0224-0002 to have a mass corresponding to a central velocity dispersion of ∼1000 km s-1, consistent with the measured optical richness of the cluster. This preliminary model is also used to estimate redshifts for all lensed components visible in our ground-based imaging. RCS 0224-0002 is the highest-redshift cluster to show lensing with such a large number of bright arcs (comparable to the best lensing clusters at much lower redshifts), and the highest-redshift strong-lensing cluster for which both the cluster redshift and at least one source redshift have been established spectroscopically, and as such it provides a powerful opportunity to directly measure the geometry of the universe and galaxy properties at high redshift.
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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 | 0.000 |
| 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".