Details

Autor(en) / Beteiligte

• Nayak, O.
• Meixner, M.
• Okada, Y.
• Lee, M. Y.
• Chevance, M.
• Buchbender, C.
• Fukui, Y.
• Onishi, T.
• Parikka, A.
• Stutzki, J.

Titel

Stellar Feedback on the Earliest Stage of Massive Star Formation

Ist Teil von

• The Astrophysical journal, 2021-02, Vol.907 (2), p.106

Ort / Verlag

Philadelphia: The American Astronomical Society

Erscheinungsjahr

2021

Quelle

EZB Electronic Journals Library

Beschreibungen/Notizen

• Abstract We report SOFIA/GREAT observations of high- J CO lines and [C ii ] observations of the super star cluster candidate H72.97-69.39 in the Large Magellanic Cloud (LMC), which is in its very early formation stage. We use our observations to determine if shocks are heating the gas or if photon-dominated regions (PDRs) are being heated by local far-UV radiation. We use a PDR model and a shock model to determine whether the CO and [C ii ] lines arise from PDRs or shocks. We can reproduce the observed high- J CO and [C ii ] emission with a clumpy PDR model with the following properties: a density of 10 4.7 cm −3 , a mass of 10 4 M ⊙ , and UV radiation of 10 3.5 in units of Draine field. Comparison with the ALMA beam-filling factor suggests a higher density within the uncertainty of the fit. We find the lower-limit [C ii ]/total infrared (TIR) ratio ( ϵ ) traced by [C ii ]/TIR to be 0.026%, lower than other known young star-forming regions in the LMC. Our shock models may explain the CO (16−15) and CO (11−10) emission lines with shock velocity of 8–11 km s −1 , pre-shock density of 10 4 –10 5 cm −3 , and G UV  = 0 in units of Draine field. However, the [C ii ] line emission cannot be explained by a shock model, thus it is originating in a different gas component. Observations of [O i ] 63 μ m predicted to be 1.1 × 10 −13 W m −2 by PDR models and 7.8 × 10 −15 W m −2 by shock models will help distinguish between the PDR and shock scenarios.