GSH 23.0−0.7+117: A Neutral Hydrogen Shell in the Inner Galaxy
Bibliographic record
Abstract
GSH 23.0-0.7+117 is a well-defined neutral hydrogen shell discovered in the Very Large Array (VLA) Galactic Plane Survey (VGPS). Only the blueshifted side of the shell was detected. The expansion velocity and systemic velocity were determined through the systematic behavior of the H I emission with velocity. The center of the shell is at ( l , b , v ) = (23 05, - 0 77, + 117 km s -1 ). The angular radius of the shell is 6 8, or 15 pc at a distance of 7.8 kpc. The H I mass divided by the volume of the half-shell implies an average density n H = 11 ± 4 cm -3 for the medium in which the shell expanded. The estimated age of GSH 23.0-0.7+117 is 1 Myr, with an upper limit of 2 Myr. The modest expansion energy of 2 × 10 48 ergs could have been provided by the stellar wind of a single O4-O8 star over the age of the shell. The 3 σ upper limit to the 1.4 GHz continuum flux density ( S 1.4 < 248 mJy) is used to derive an upper limit to the Lyman continuum luminosity generated inside the shell. This upper limit implies a maximum of one O9 star (i.e., O8-O9.5, taking into account the error in the distance) inside the H I shell, unless most of the incident ionizing flux leaks through the H I shell. To allow this, the shell should be fragmented on scales smaller than the beam (2.3 pc). If the stellar wind bubble is not adiabatic or the bubble has burst (as suggested by the H I channel maps), agreement between the energy and ionization requirements is even less likely. The limit set by the nondetection in the continuum provides a significant challenge for the interpretation of GSH 23.0-0.7+117 as a stellar wind bubble. A similar analysis may be applicable to other Galactic H I shells that have not been detected in the continuum.
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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 | 0.000 | 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) | 0.003 | 0.001 |
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".