We present the main results of the Ph.D. thesis carried out by López-Sánchez (Ph.D. thesis, 2006), in which a detailed morphological, photometric and spectroscopic analysis of a sample of 20 Wolf-Rayet (WR) galaxies was performed. The main aims are the study of the star formation and O and WR stellar populations in these galaxies, and the role that

Magnetic reconnection is thought to drive a wide variety of dynamic phenomena in the solar atmosphere. Yet, the detailed physical mechanisms driving reconnection are difficult to discern in the remote sensing observations that are used to study the solar atmosphere. In this Letter, we exploit the high-resolution instruments Interface Region Imaging

Context. The mechanisms giving rise to diffuse radio emission in galaxy clusters and, in particular, their connection with cluster mergers are still being debated. Aims: We explore the internal dynamics of Abell 2254, which has been shown to host a very clumpy and irregular radio halo. Methods: Our analysis is mainly based on redshift data for 128

We took simultaneous observations in Fe I 1.5 µ and Fe I 630 nm of an internetwork region. We discuss the compatibility of the data in the two spectral ranges, and present results for the magnetic field distribution. We show that the larger contribution comes from hG field strengths.

During the first few nights following its discovery, we observed the interstellar Ca II and Na I lines towards supernova 1993J at high spectral resolution (full width half maximum (FWHM) approximately 5-6 km/s) with the William Herschel Telescope at La Palma. We find a crowd of absorption components in the radial-velocity range -135 km/s less than

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