Aims: We present a new approach to study the mass-metallicity relation and its dependency on time. Methods: We used the star formation history (SFH) derived from color-magnitude diagram fitting techniques of a sample of Local Group (LG) dwarfs to obtain stellar masses, metallicities, and star-formation rates (SFR) to analyze the mass-metallicity

Aims: We performed a comprehensive analysis of a sample of 20 starburst galaxies that show a substantial population of very young massive stars, most of them classified as Wolf-Rayet galaxies. Methods: In this paper, the last in the series, we analyze the global properties of our galaxy sample using multiwavelength data extracted from our own

An unsettled question concerning the formation and distribution of massive stars is whether they must be born in massive clusters and, if found in less dense environments, whether they must have migrated there. With the advent of wide-area digital photometric surveys, it is now possible to identify massive stars away from prominent Galactic

Massive stars are key ingredients in the evolution of the Universe. Yet, important uncertainties and limits persist in our understanding of these objects, even in their early phases, limiting their application as tools to interpret the Universe. Here we review some of these open questions and argue that large samples are needed to answer them, both

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We observed the optical counterpart of MAXI J1836-194 (Negoro et al., ATel#3611; Kennea et al., ATel#3613) with the 82cm IAC80 telescope at the Observatorio del Teide, Tenerife, Spain. We acquired 94 I-band images on Sep 28.83079--28.93356 UT (starting 39 minutes after Swift trigger 504307; Barthelmy et al., GCN 12405) with an exposure time of 1