WHAT DRIVES THE EXPANSION OF GIANT H ii REGIONS?: A STUDY OF STELLAR FEEDBACK IN 30 DORADUS

By L. Lopez, Mark R. Krumholz, A. Bolatto, J. Xavier Prochaska, E. Ramirez-Ruiz. 2010

139 citations recorded by the source corpus.

Observations show that star formation is an inefficient and slow process. This result can be attributed to the injection of energy and momentum by stars that prevents free-fall collapse of molecular clouds. The mechanism of this stellar feedback is debated theoretically; possible sources of pressure include the classical warm H ii gas, the hot gas generated by shock heating from stellar winds and supernovae, direct radiation of stars, and the dust-processed radiation field trapped inside the H ii shell. In this paper, we measure observationally the pressures associated with each component listed above across the giant H ii region 30 Doradus in the Large Magellanic Cloud. We exploit high-resolution, multi-wavelength images (radio, infrared, optical, ultraviolet, and X-ray) to map these pressures as a function of position. We find that radiation pressure dominates within 75 pc of the central star cluster, R136, while the H ii gas pressure dominates at larger radii. By contrast, the dust-processed radiation pressure and hot gas pressure are generally weak and not dynamically important, although the hot gas pressure may have played a more significant role at early times. Based on the low X-ray gas pressures, we demonstrate that the hot gas is only partially confined and must be leaking out the H ii shell. Additionally, we consider the implications of a dominant radiation pressure on the early dynamics of 30 Doradus.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/6d7a9f9fb501d84d2c8c926a81327ed6bf7310fc

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Citations in the corpus

Feedback from winds and supernovae in massive stellar clusters – I. Hydrodynamics (2012, background): “This scenario has received backing from Lopez et al. (2011) who conclude that such leakage may be occuring within 30 Doradus.”
Before the first supernova: combined effects of H II regions and winds on molecular clouds (2014, unknown): “Lopez et al. (2011) studied the 30 Doradus region, comparing the radiation pressure, ionized gas pressure and X–ray emitting gas pressure as a function of radius from the R136 cluster.”
Galaxies on FIRE (Feedback In Realistic Environments): stellar feedback explains cosmologically inefficient star formation (2013, background): “The same result is found (on smaller scales) in much higher-resolution simulations of either single star clusters or the first stars, which directly treat the radiation-hydrodynamics with each single star as a source (e.g. Offner et al. 2009; Krumholz et al. 2011; Tasker 2011; Wise et al. 2012).”
Self-regulated star formation in galaxies via momentum input from massive stars (2011, background): “Interestingly, recent observations of massive stars (Freyer, Hensler & Yorke 2006) and star-forming regions (Lopez et al. 2011) have suggested similar ∼1 per cent efficiencies for transfer of luminous energy into bulk motions and (post-shock) thermal energy.”
Gusty, gaseous flows of FIRE: Galactic winds in cosmological simulations with explicit stellar feedback (2015, background): “These ‘early feedback’ mechanisms act before SNe, heating and stirring the surrounding ISM which is necessary to match conditions in star-forming regions such as Carina (Harper-Clark & Murray 2009) and 30 Dor (Lopez et al. 2011; Pellegrini, Baldwin & Ferland 2011).”
FIRE-2 simulations: physics versus numerics in galaxy formation (2017, background): “Observationally, many stellar feedback processes – SNe, protostellar jets, photo-heating, stellar mass loss (O-star and AGB winds), and radiation pressure – act efficiently on the ISM (see Evans et al. 2009; Lopez et al. 2011, and references above).”
The EAGLE simulations of galaxy formation: calibration of subgrid physics and model variations (2015, background): “First, it is not known what are the energy, momentum and mass fluxes incident upon the ISM and star-forming complexes therein (but see Lopez et al. 2011; Rosen et al. 2014), due to mechanisms such as radiation pressure and winds from Oclass stars, asymptotic giant branch (AGB) stars and active…”
A characteristic oxygen abundance gradient in galaxy disks unveiled with CALIFA (2013, background): “…H ii regions have a typical physical size of about a hundred 4 http://www.caha.es/sanchez/HII_explorer/ or a few hundred parsecs (e.g., González Delgado & Perez 1997; Lopez et al. 2011; Oey et al. 2003), which corresponds to a typical projected size of a few arcsec at the distance of the galaxies.”