Metal-poor ultracool dwarfs (ultracool subdwarfs, including very-low-mass stars and brown dwarfs) are tracers of the pristine chemical composition at early phases in the assembly of the Milky Way. They are poorly understood because they are extremely faint and rare. Our aims are to improve the knowledge of ultracool subdwarf candidates, to break

Over the past decade, microlensing surveys in field stars and the Gaia-informed census of nearby star-forming regions have convincingly demonsrated the presence of a significant population of free-floating planetary-mass objects. The origin of these objects is still debated, with the main plausible scenarios being: the dynamical ejection from a

MUDEHaR has completed its first of five years of project, and all the information is already available for exploitation. MUDEHaR is a multi-epoch photometric survey with two narrow filters in Hα and the calcium triplet window that uses T80Cam at the JAST80 telescope at Javalambre spanish astronomical observatory. It is obtaining ~50 epochs/year per