The Absorption and Emission Kinematics in the<i>z</i> = 0.7450 Mg<scp>ii</scp>Absorber toward Q1331+17
Bibliographic record
Abstract
We present a comparative analysis of the galaxy emission and quasar (QSO) absorption kinematics of a z abs ~ 0.7450 Mg II system and its candidate absorbing galaxy (G5) located 3 86 (28.3 h kpc) from the QSO. We have obtained a spectrum of the galaxy candidate, previously identified as a luminous edge-on disk, and detect the [O II] λ3727 doublet at a systemic redshift of z sys = 0.7450. From slit spectroscopy of this galaxy, we find v rot ≳ 210 km s -1 , possibly as large as 350 km s -1 . Plotted on the same velocity scale, the systemic redshift of the galaxy coincides with the center of the absorption system, although the absorption components span more than 100 km s -1 in either direction. However, once the sense of the rotation is taken into account, there is no absorbing gas at the projected velocity of the disk rotation curve. This implies incompatibility with a simple disk scenario. Moreover, a reanalysis of archival Hubble Space Telescope ( HST ) data reveals that the galaxy is only 0.3 L * , considerably less luminous than previously reported in the literature. This is incompatible with the established Tully-Fisher relation at this redshift, unless approximately 2 mag of total extinction is invoked. Careful inspection of the archival HST data reveals that G5 may well be composed of two galaxies, although the quality of the data does not permit a detailed investigation of this. This possibility is further supported by the identification of a second faint emission line at λ obs = 5674 Å, whose distinct spatial and velocity profiles indicate that it arises in a different galaxy at a different redshift. Analysis of the absorption lines shows evidence for superbubbles in the interstellar medium of the absorbing galaxy, based on the striking symmetry between components and large Mg I/Mg II and Mg I/Fe II ratios, indicative of large densities. The large velocity separations between line pairings, Δ v ~ 150 km s -1 , indicate that these bubbles may be powered by OB associations comparable to the largest observed at z = 0 and that the gas is probably enriched to at least 1/10 solar metallicity. This is consistent with observations at low redshift that extended Mg II halos are often seen in galaxies that contain disturbed gas. Superbubbles may also explain why the absorber has a relatively large Mg II equivalent width relative to the luminosity of the associated galaxy (or galaxies).
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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 | 0.001 |
| 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".