SHOCK-ENHANCED C<sup>+</sup>EMISSION AND THE DETECTION OF H<sub>2</sub>O FROM THE STEPHAN'S QUINTET GROUP-WIDE SHOCK USING<i>HERSCHEL</i>
Bibliographic record
Abstract
<p>\n\tWe present the first Herschel spectroscopic detections of the [O I] 63 {$μ$}m and [C II] 158 {$μ$}m fine-structure transitions, and a single para-H$_{2}$O line from the 35 {\times} 15 kpc$^{2}$ shocked intergalactic filament in Stephan's Quintet. The filament is believed to have been formed when a high-speed intruder to the group collided with a clumpy intergroup gas. Observations with the PACS spectrometer provide evidence for broad ({gt}1000 km s$^{–1}$) luminous [C II] line profiles, as well as fainter [O I] 63 {$μ$}m emission. SPIRE FTS observations reveal water emission from the p-H$_{2}$O (1$_{11}$-0$_{00}$) transition at several positions in the filament, but no other molecular lines. The H$_{2}$O line is narrow and may be associated with denser intermediate-velocity gas experiencing the strongest shock-heating. The [C II]/PAH$_{tot}$ and [C II]/FIR ratios are too large to be explained by normal photo-electric heating in photodissociation regions. H II region excitation or X-ray/cosmic-ray heating can also be ruled out. The observations lead to the conclusion that a large fraction the molecular gas is diffuse and warm. We propose that the [C II], [O I], and warm H$_{2}$ line emission is powered by a turbulent cascade in which kinetic energy from the galaxy collision with the intergalactic medium is dissipated to small scales and low velocities, via shocks and turbulent eddies. Low-velocity magnetic shocks can help explain both the [C II]/[O I] ratio, and the relatively high [C II]/H$_{2}$ ratios observed. The discovery that [C II] emission can be enhanced, in large-scale turbulent regions in collisional environments, has implications for the interpretation of [C II] emission in high-z galaxies. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.</p>
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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 | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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".