An Extremely Bright Echo Associated with SN 2002hh
Bibliographic record
Abstract
We present new, very late time optical photometry and spectroscopy of the interesting Type II-P supernova SN 2002hh, in NGC 6946. Gemini/GMOS-N has been used to acquire visible spectra at six epochs between 2004 August and 2006 July, following the evolution of the SN from age 661 to 1358 days. Few optical spectra of Type II supernovae with ages greater than 1 yr exist. In addition, g ', r ', and i ' images were acquired at all six epochs. The spectral and photometric evolution of SN 2002hh has been very unusual. Measures of the brightness of this SN, both in the R and I bands, as well as in the Hα emission flux, show no significant fading over an interval of nearly 2 years. The most straightforward explanation for this behavior is that the light being measured comes not only from the SN itself but also from an echo off nearby dust. Echoes have been detected previously around several SNe, but these echoes, at their brightest, were ~8 mag below the maximum brightness of the SN. At V ~ 21 mag, the putative echo dominates the light of SN 2002hh and is only ~4 mag below the outburst's peak brightness. There is an estimated 6 mag of total extinction in V toward SN 2002hh. The proposed explanation of a differential echo/SN absorption is inconsistent with the observed BVRI colors.
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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 | 0.001 | 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) | 0.001 | 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".