The journey of ionising photons through the porous ISM of galaxies

• Antragstellerinnen / Antragsteller: Professorin Barbara Ercolano, Ph.D.; Professor Dr. Thomas Preibisch
• Fachliche Zuordnung: Astrophysik und Astronomie
• Förderung: Förderung von 2011 bis 2018
• Projektkennung: Deutsche Forschungsgemeinschaft (DFG) - Projektnummer 203381016

The interstellar medium (ISM) in our Galaxy and others is dramatically influenced by feedback from massive stars, which, while relatively rare by numbers, dominate the energetics in the ISM through ionising radiation, stellar winds and supernova events. One fundamental question, that has received a large amount of attention without a definitive answer, is what fraction, fesc, of the ionising photons from these massive stars is able to escape from the host galaxy. Current estimates range from 0 to ~ 100%, an estimate that is largely dependant on assumptions made for the ISM structure. The exact fraction, and any variation with environment, is crucial for understanding the energy budget of the ISM within galaxies, impacts the inferred stellar initial mass function and the star-formation rate of galaxies, and, at high redshift, determines the role that massive stars play in the reionisation of the Universe. Here we propose a novel two pronged approach to address this important problem, consisting of: (i) detailed 3D radiative transfer and photoionisation models of idealised and realistic galaxies, that include a hydrodynamical treatment of the ISM, to predict fesc ; (ii) a systematic observational programme, based on ground and space based imaging and spectroscopy of nearby galaxies, to infer fesc as a function of environment; Our realistic radiative transfer models will provide a key link between theory and observations and will allow us to identify useful diagnostics for the properties of the ISM and fesc in our own and other galaxies.

• DFG-Verfahren: Schwerpunktprogramme
• Teilprojekt zu: SPP 1573: Physics of the Interstellar Medium