The unusual UV continuum of quasar Ton 34 and the possibility of crystalline dust absorption
Bibliographic record
Abstract
\n Context.Luminous quasars are known to display a sharp steepening\nof the continuum near 1100 Å. This spectral feature is not well\nfitted by current accretion disk models, unless Comptonization of\nthe disk emission is invoked. Absorption by carbon crystalline dust\nhas been proposed to account for this feature.\n Aims.Ton 34 (zq = 1.928)\nexhibits the steepest far-UV decline $(\\hbox{$F_\\nu$}\\propto \\nu^{-5.3})$\namong the 183 quasar HST-FOS spectra analyzed by Telfer et al.\n(2002, ApJ, 565, 773). It is an ideal object to test the crystalline dust\nhypothesis as well as alternative interpretations of the UV\nbreak.\n Methods.We reconstruct the UV spectral energy distribution of Ton 34 by combining HST, IUE and Palomar spectra.\n Results.The far-UV continuum\nshows a very deep continuum trough, which is bounded by a steep\nfar-UV rise. We fit the trough assuming nanodiamond dust\ngrains.\n Conclusions.Extinction by carbon crystalline dust reproduces the deep\nabsorption trough of Ton 34 reasonably well, but not the observed\nsteep rise in the extreme UV. We also study the possibility of an\nintrinsic continuum rollover. The dust might be part of a high\nvelocity outflow ($\\simeq $13 000 km s-1), which is observed in\nabsorption in the lines of C <sc>IV</sc> λ1549, O <sc>VI</sc> λ1035, N <sc>V</sc> λ1240 and Lyα.\n
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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 | 0.001 | 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 | 0.002 |
| 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".