The OTELO project is the extragalactic survey currently under way using the tunable filters of theinstrument OSIRIS at the GTC. OTELO is providing the deepest emission line object survey of the universe up to a redshift 7. In this contribution, the first images will be shown together with some preliminary results.

The Groth field is one of the sky regions that will be targeted by the OSIRIS Tunable Filter Emission Line Object survey in the optical 820 nm and 920 nm atmospheric windows. In the present paper, public Chandra X-ray data with total exposure time of 200 ks are analyzed and combined with optical broadband data of the Groth field, in order to study

We have performed a detailed oxygen abundance analysis of 23 metal-poor (-3.0 [Fe/H] -0.3) unevolved halo stars and one giant through the OH bands in the near UV, using high-resolution echelle spectra. Oxygen is found to be overabundant with respect to iron in these stars, with the [O/Fe] ratio increasing from 0.6 to 1 between [Fe/H] = -1.5 and

We present in this contribution a review of recent results of parameters of massive OB stars in the Milky Way, the Magellanic Clouds and nearby spirals. The review is timely because of the strong lowering of the temperature scale of Galactic OB stars produced by the new model atmospheres, including sphericity, blanketing and mass-loss, that are

We report the first reliable measurement of the nebular [OI] 5577AA emission line in the Orion nebula. The use of diagnostic diagrams using the nebular [OI] and [NI] lines and the comparison with available photoionization models, indicate that the bulk of the nebular emission of the neutral ionic species in the Orion nebula is produced in regions

Measuring vector magnetic fields in the solar atmosphere using the profiles of the Stokes parameters of polarized spectral lines split by the Zeeman effect is known as Stokes Inversion. This inverse problem is usually solved by least-squares fitting of the Stokes profiles. However least-squares inversion is too slow for the new generation of solar