I am a postdoctoral researcher working on high redshift galaxies during the Epoch of Reionization using cosmological and idealized radio-hydrodynamical simulations.
During my PhD, I studied low-mass galaxies at z > 6, with a specific focus on how ionizing radiation produced by massive stars can escape the galaxy. Because they are so numerous, low-mass galaxies are thought to be the main contributor to the ionizing budget during the Epoch of Reionization. Characterizing how much radiation they leak in the intergalactic medium is thus necessary to put constraint on the ionization history of the Universe.
One of the conclusions of my work was that escape of ionizing radiation is intimately tied to stellar feedback, supernovae and ionizing radiaiton, which is necessary to reduce the amount of neutral gas around young star clusters.
The figure below shows temperature maps of a galaxy before (left), at the beginning (middle) and a few million years after (right) a massive stellar feedback event.
We could quantify the fraction of radiation that escapes the galaxy (in red) is correlated to the star formation rate (in blue) and to the outflows driven by supernovae explosions (in yellow), as shown in the figure below.
Recently, it has been suggested that faint AGNs could significantly contribute to the high redshift ionizing budget, in stark contrast to previous studies. However the properties of these objects and of their hosts galaxies are poorly known, and especially how much of the ionizing radiation from the central AGN can actually escape. This is exactly where my work within the BLACK group falls.