Valentina Luridiana

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This paper describes a new determination of the primordial helium abundance (Y P), based on the abundance analysis of five metal-poor extragalactic H ii regions. For three regions of the sample (SBS 0335–052, I Zw 18, and H 29) we present tailored photoionization models based on improved calculations with respect to previous models. In particular, we use(More)
The presently accepted " Theory of the Universe " was pioneered 60 years ago by Gamow, Alpher and Herman. As a consequence of the, later dubbed, Hot Big-Bang, matter was neutrons, and after some decay protons, and a history of successive captures built up the elements. It wasn't until some 15 years later (with the discovery of the Cosmic Microwave(More)
We present a review on the determination of the primordial helium abundance , Y p , based on the study of hydrogen and helium recombination lines in extragalactic H ii regions. We also discuss the observational determinations of the increase of helium to the increase of oxygen by mass ∆Y /∆O, and compare them with predictions based on models of galactic(More)
We present IACTalks, a free and open access seminars archive ( aimed at promoting astronomy and the exchange of ideas by providing high-quality scientific seminars to the astronomical community. The archive of seminars and talks given at the Instituto de Astrofísica de Canarias goes back to 2008. Over 360 talks and seminars are now(More)
We present high resolution spectroscopic data of the two giant extragalactic H II regions NGC 5461 and NGC 5471 in M101, which have been obtained with the 2.1-m telescope of the Observatorio Astronómico Nacional in San Pedro Mártir, Baja California. We measured the intensities of several H and He recombination lines, and of forbidden lines of a large number(More)
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