Shaping the structure of a GMC with radiation and winds

Decataldo, D.; Lupi, A.; Ferrara, A.; Pallottini, A.; Fumagalli, M.

Abstract

We study the effect of stellar feedback (photodissociation/ionization, radiation pressure and winds) on the evolution of a Giant Molecular Cloud (GMC), by means of a 3D radiative transfer, hydro-simulation implementing a complex chemical network featuring H2 formation and destruction. We track the formation of individual stars with mass M > 1 M⊙ with a stochastic recipe. Each star emits radiation according to its spectrum, sampled with 10 photon bins from near-infrared to extreme ultra-violet bands; winds are implemented by energy injection in the neighbouring cells. We run a simulation of a GMC with mass M = 105 M⊙, following the evolution of different gas phases. Thanks to the simultaneous inclusion of different stellar feedback mechanisms, we identify two stages in the cloud evolution: (1) radiation and winds carve ionized, low-density bubbles around massive stars, while FUV radiation dissociates most H2 in the cloud, apart from dense, self-shielded clumps; (2) rapid star formation (SFR≃ 0.1 M⊙  − 1) consumes molecular gas in the dense clumps, so that UV radiation escapes and ionizes the remaining HI gas in the GMC. H2 is exhausted in 1.6 Myr, yielding a final star formation efficiency of 36 per cent. The average intensity of FUV and ionizing fields increases almost steadily with time; by the end of the simulation (t = 2.5 Myr) we find 〈G0〉 ≃ 103 (in Habing units), and a ionization parameter 〈Uion〉 ≃ 102, respectively. The ionization field has also a more patchy distribution than the FUV one within the GMC. Throughout the evolution, the escape fraction of ionizing photons from the cloud is fion, esc ≲ 0.03.

Citation

Decataldo, D., Lupi, A., Ferrara, A., Pallottini, A., & Fumagalli, M. (2020). Shaping the structure of a GMC with radiation and winds. Monthly Notices of the Royal Astronomical Society, 497(4), 4718-4732. https://doi.org/10.1093/mnras/staa2326

• Journal Article Type: Article
• Acceptance Date: Jul 30, 2020
• Online Publication Date: Aug 11, 2020
• Publication Date: 2020-10
• Deposit Date: Aug 12, 2020
• Publicly Available Date: Sep 18, 2020
• Journal: Monthly Notices of the Royal Astronomical Society
• Print ISSN: 0035-8711
• Electronic ISSN: 1365-2966
• Publisher: Royal Astronomical Society
• Peer Reviewed: Peer Reviewed
• Volume: 497
• Issue: 4
• Pages: 4718-4732
• DOI: https://doi.org/10.1093/mnras/staa2326
• Public URL: https://durham-repository.worktribe.com/output/1263801