In this thesis we explore the OTELO (OSIRIS Tunable Filter Emission Line Object) survey. OTELO is a very deep, pencil beam survey for the search of emission line sources by means of the tunable filters of the OSIRIS instrument, installed at the Gran Telescopio Canarias. A tomography scan method results in 2D, low-resolution pseudo-spectra for all

One of the most exciting areas of astronomical research today is the study of exoplanetary systems, engaging the imagination not only of the astronomical community but also of the general public. Since the Nobel-winning discovery of a giant planet around the Sun-like star 51 Pegasi (Mayor & Queloz, 1995), about 4000 extra-solar planets have been

We compute the expected sensitivity on measurements of optical depth to reionization for a ground-based experiment at Teide Observatory. We simulate polarized partial sky maps for the GroundBIRD experiment at the frequencies 145 and 220 GHz. We perform fits for the simulated maps with our pixel-based likelihood to extract the optical depth to

Although true metal-free "Population III" stars have so far escaped discovery, their nature, and that of their supernovae, is revealed in the chemical products left behind in the next generations of stars. Here we report the detection of an ultra-metal-poor star in the Sculptor dwarf spheroidal galaxy AS0039. With [Fe/H] LTE = -4.11, it is the most