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Esta tesis está enfocada hacia el estudio de la interacción de las estrellas masivas con el medio interestelar ionizado en dos regiones HII galácticas. Se presentan dos estudios bien diferenciados. El primero trata de la comparación de abundancias químicas en la región de formación estelar asociada con la Nebulosa de Orión (M42), obtenidas a partir

The Local Group Census is a narrowband imaging survey aimed at cataloguing the emission-line populations in the galaxies of the Local Group. Data, which were obtained using the Wide Field Camera of the 2.5m Isaac Newton Telescope, are available to the whole astronomical community, resulting in a valuable imaging resource for follow-up spectroscopy

IPHAS is a deep, fully photometric H α survey of the northern Galactic plane carried out with the Isaac Newton telescope at La Palma. The IPHAS point source Hα catalogue (complete up to r=19.5 mag) will be a prime source for GTC programs related to important short-lived (and poorly known) stages of evolution: pre- and post-main sequence stars, the

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We present time-resolved optical spectroscopy and photometry of four relatively bright (V˜14.0-15.5) long-period cataclysmic variables (CVs) discovered in the Hamburg Quasar Survey: HS 0139+0559, HS 0229+8016, HS 0506+7725, and HS 0642+5049. Their respective orbital periods, 243.69±0.49 min, 232.550±0.049 min, 212.7±0.2 min, and 225.90±0.23 min are