This contribution is focused on the innovative aspects of the design of the Laser Guide Star (LGS) Facility for the Gran Telescopio Canarias (GTC) Adaptive Optics (GTCAO) System [6]. After a trade-off process considering different alternatives, a preliminary opto-mechanical design was defined, based on a "TOPTICA SodiumStar" laser to be launched on

Context. Cosmic chronometers may be used to measure the age difference between passively evolving galaxy populations to calculate the Hubble parameter H(z) as a function of redshift z. The age estimator emerges from the relationship between the amplitude of the rest frame Balmer break at 4000 Å and the age of a galaxy, assuming that there is one

We report on 16 BL Lacertae objects that were proposed to be at z > 1. We present spectroscopic observations secured at the 10.4 m GTC that allowed us to assess the redshift of these sources. In particular, for five objects, we disprove the previous value of the redshift reported in the literature and found that they lie at z 1. Moreover, two of

Context. Knowing the exact shape of the ultraviolet (UV) luminosity function (LF) of high-redshift galaxies is important to understand the star formation history of the early Universe. However, the uncertainties, especially at the faint and bright ends of the LFs, remain significant. Aims: In this paper, we study the UV LF of redshift z = 2.5 - 4.5

HARMONI is a visible and near-infrared (0.5 to 2.45 μm) integral field spectrograph, providing the E-ELT's core spectroscopic capability, over a range of resolving powers from R (λ/Δλ) 3500 to 18000. The instrument provides simultaneous spectra of ˜32000 spaxels arranged in a sqrt(2):1 aspect ratio contiguous field. The pre-optics take light

The Gran Telescopio Canarias Adaptive Optics (GTCAO) is a single-conjugated post-focal system with a Shack Hartmann wavefront sensor working at visible wavelength and one Deformable Mirror (DM) conjugated to the pupil. GTCAO does not include a fast tip-tilt mirror in its optical bench so it relies on the telescope secondary mirror (M2) to correct