VLT integral field spectroscopy of embedded protostars: using near-infrared emission lines as tracers of accretion and outflow
Notice bibliographique
Résumé
Aims. We present near-infrared spectroscopy of the forbidden emission line (FEL) and molecular hydrogen emission line (MHEL) regions at the bases of Herbig-Haro (HH) jets from seven embedded protostars: SVS 13 (the HH 7-11 progenitor), HH 26-IRS, HH 34-IRS, HH 72-IRS, HH 83-IRS, HH 300-IRS (IRAS 04239+2436) and HH 999-IRS (IRAS 06047-1117) Methods. The integral field spectrograph, SINFONI, on the European Southern Observatory's Very Large Telescope (VLT) was used to characterise jet parameters in these formative regions, where the jets are collimated and accelerated. Results. We find considerable differences in the spectra of HH 83-IRS when compared to the other six sources; CO bandhead and atomic permitted lines from Ca i, Na i, Mg i and Al i are observed in emission in all but HH 83-IRS, where they are detected in absorption. It is likely that this source is more evolved than the others (or at the very least considerably less active). Strong CO bandhead emission is also detected in emission in the other six sources, while extended H 2 ro-vibrational and [Fe ii] forbidden emission lines trace the outflows (only the HH jet from HH 83-IRS is undetected). CO bandhead and Br emission peaks are in most cases coincident with the jet source continuum position, consistent with excitation in an accretion disk or accretion flow. However, in the closest source, HH 300-IRS, we do find evidence for excitation in the outflow: here the emission peak is offset by 3.6(0.7) AU along the flow axis. We also note a correlation between CO and Mg i, Na i and Ca i intensities, which supports the idea that these atomic permitted lines are associated with accretion disks. From H 2 and [Fe ii] images we measure jet widths and derive upper limits to flow component opening angles. Although we do not find that the ionised [Fe ii] component is consistently narrower than the H 2 flow component, we do find that narrower H 2 and/or [Fe ii] flow components are associated with higher radial velocities (as reported in the literature). Flow opening angles, over the first few hundred AU in each source, are measured to be in the range 21 -42 in both H 2 and [Fe ii]. Finally, from our 3-D data we are also able to map the extinction and electron density at the base of the outflows from some of our targets: within a few hundred AU, both decrease sharply with distance from the source. Conclusions. It seems clear that collimated atomic and molecular jets, which may initially exhibit a wide opening angle, are a feature of outflows from Class I protostars, Class II T Tauri stars, and possibly even Class 0 sources, and that these jets can be traced to within a few hundred AU of the driving source. A common jet collimation and acceleration mechanism seems inescapable for all stages of low mass star formation.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule tête enseignante, pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».