Type IIn Supernova Detections in z ~ 2 Lyman Break Galaxies: Probing the IMF Directly
Bibliographic record
Abstract
Type IIn supernovae (SNe IIn) exhibit luminous ultraviolet continua during outburst and luminous, long-lived narrow ultraviolet and optical emission lines attributed to circumstellar interaction. These properties have enabled successful detections at z ~ 2 in archival imaging and continued investigations from late-time spectroscopy. Because SNe IIn are believed to have massive (≳50M_☉) progenitors, searches in the well-studied Lyman break galaxy (LBG) host population offer the prospect of testing the form of the high-redshift stellar initial mass function (IMF) in a high density star formation environment directly. I briefly discuss our z ~ 2 photometric detection method targeting LBGs in the Canada-France-Hawaii Telescope Legacy Survey (CFHTLS) and present data from the first 6 confirmed z ~ 2 SNe IIn pulled from 30 photometric SN candidates. A comparison of the color and magnitude distributions of the SN host galaxies to that of the full LBG sample finds that z ~ 2 SNe preferentially occur in bluer, fainter galaxies. I conclude with a discussion of an approach that uses the CFHTLS pilot sample to provide a first estimate of the form of the high-redshift IMF. Upcoming deep synoptic imaging surveys will greatly improve z ~ 2 SNe IIn statistics from ~10^5 expected detections and future large aperture space- and ground-based telescopes will have the sensitivities to extend this work to z ≳ 6.
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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) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.002 |
| 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 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".