Two lensed Lyman-a emitting galaxies at at z~Â 5
Bibliographic record
Abstract
We present observations of two strongly lensed z ~ 5 Lyman-α emitting galaxies that were discovered in the Sloan Giant Arcs Survey (SGAS). We identify the two sources as SGAS J091541+382655 at z = 5.200 and SGAS J134331+415455 at z = 4.994. We measure their AB magnitudes at (i, z) = (23.34 ± 0.09, 23.29 ± 0.13) mag and (i, z) = (23.78 ± 0.18, 24.24+0.18 –0.16) mag and the rest-frame equivalent widths of the Lyman-α emission at 25.3 ± 4.1 Ã… and 135.6 ± 20.3 Ã… for SGAS J091541+382655 and SGAS J134331+415455, respectively. Each source is strongly lensed by a massive galaxy cluster in the foreground, and the magnifications due to gravitational lensing are recovered from strong lens modeling of the foreground lensing potentials. We use the magnification to calculate the intrinsic, unlensed Lyman-α and UV continuum luminosities for both sources, as well as the implied star formation rates. We find SGAS J091541+382655 and SGAS J134341+415455 to be galaxies with (L Ly–α, L UV) <= (0.6 L* Ly–α, 2 L*UV) and (L Ly–α, L UV) = (0.5 L* Ly–α, 0.9 L*UV), respectively. Comparison of the spectral energy distributions of both sources against stellar population models produces estimates of the mass in young stars in each galaxy; we report an upper limit of M stars <= 7.9+3.7 –2.5 × 107 M sun h –1 0.7 for SGAS J091531+382655 and a range of viable masses for SGAS J134331+415455 of 2 × 108 M sun h –1 0.7< M stars < 6 × 109 M sun h –1 0.7. Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the Science and Technology Facilities Council (United Kingdom), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), Ministério da Ciência e Tecnologia (Brazil) and Ministerio de Ciencia, TecnologÃa e Innovación Productiva (Argentina), and the Apache Point Observatory 3.5 m telescope, which is owned and operated by the Astrophysical Research Consortium.
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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 | 0.001 | 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) | 0.001 | 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".