We show herein that a proto-cluster of Ly α emitting galaxies, spectroscopically confirmed at redshift 6.5, produces a remarkable number of ionizing continuum photons. We start from the Ly α fluxes measured in the spectra of the sources detected spectroscopically. From these fluxes, we derive the ionizing emissivity of continuum photons of the

Mass, radius and age are three of the most fundamental parameters for celestial objects, enabling insight into the evolution and internal physics of stars, brown dwarfs and planets. Brown dwarfs are hydrogen-rich objects that are unable to sustain core fusion reactions but are supported against collapse by electron degeneracy pressure 1. As they

White dwarfs are the burnt-out cores of Sun-like stars and are the fate of 97 per cent of the stars in our Galaxy. The internal structure and composition of white dwarfs are hidden by their high gravities, which causes all elements apart from the lightest ones to settle out of their atmospheres. The most direct method of probing the inner structure

Present-day multiwavelength deep imaging surveys allow to characterize the outskirts of galaxies with unprecedented precision. Taking advantage of this situation, we define a new physically motivated measurement of size for galaxies based on the expected location of the gas density threshold for star formation. Employing both theoretical and

Outflows from starburst galaxies can be driven by thermal pressure, radiation, and cosmic rays. We present an analytic phenomenological model that accounts for these contributions simultaneously to investigate their effects on the hydrodynamical properties of outflows. We assess the impact of energy injection, wind opacity, magnetic field strength

The five globular clusters (GCs) of the Fornax dwarf spheroidal galaxy are puzzling for two reasons; the mass in GCs is high with respect to the galaxy's old stellar mass and their survival and large distance (>1 kpc) is at odds with naive expectations of dynamical friction. We present here a semi-analytic model, simultaneously addressing both