The Anatomy of Stellar Nurseries

• Applicant: Dr. Sacha Hony, Ph.D.
• Subject Area: Astrophysics and Astronomy
• Term: from 2015 to 2019
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 285648061

I propose to determine the structure inside star-formation complexes in our nearest neighbouring galaxies. The basic premise is that stars (and in particular high-mass stars) are not born in isolation but are formed as part of complexes that can span ~100 parsec. Understanding this mode of star formation requires detailed knowledge of the distribution of the gas and stars (at parsec scales) across these entire complexes.The project uses a powerful combination of state-of-the-art optical to sub-millimetre photometric and spectroscopic data from HST, Spitzer, Herschel and APEX to peer inside several complexes in the Magellanic Cloud galaxies to estabish the relation between the newly formed stars and their surroundings. Since I am a partner of the collaborations that worked hard to collect most of these rich data sets, I have priority access as well as in depth knowledge of their limitations.Our analysis will allow us to determine the following key parameters:* The structural parameters of the distribution of newly formed stars, allowing us to distinguish between gravitionally bound topologies and distributed, unbound stars.* The size scale on which the young stars follow the turbulent ISM.* Trends of star formation efficiency inside the complexes.* The temperature and density distribution of the interstellar gas and dust.* The location and physical conditions in the photon-dominated regions (PDR) where the strong radiation field of the high-mass stars impinges on the dense gas and significantly alters its birth environment.The originality of the project lies both in the very rich data-sets that are exploited, the range of parameters that we can probe (metallicity, age and star formation activity of the individual regions), as well as the synergy of methods that I propose to use.Specifically, we will use the following tools, several of which have been pioneered, calibrated and refined within our own works:* Stellar distributions from auto-correlation function analysis (Gouliermis, Hony, Klessen 2014)* Star formation rates from resolved pre-main sequence star counts (Hony et al. 2015)* Dust temperature and density distributions from SED fitting with Monte Carlo estimates of uncertainties (Galametz et al. 2009; Hony et al. 2010)* PDR modeling using Cloudy (Ferland at al. 2013) and the PDR toolbox (Pound & Wolfire 2008)

• DFG Programme: Research Grants