A recalibration of IUE NEWSIPS low dispersion data

While the low dispersion IUE NEWSIPS data products represent a significant improvement over original IUE SIPS data, they still contain serious systematic effects which compromise their utility for certain applications. We show that NEWSIPS low resolution data are internally consistent to only 10-15% at best, with the majority of the problem due to time dependent systematic effects. In addition, the NEWSIPS flux calibration is shown to be inconsistent by nearly 10%. We examine the origin of these problems and proceed to formulate and apply algorithms to correct them to ~ 3% level -- a factor of 5 improvement in accuracy. Because of the temporal systematics, transforming the corrected data to the IUE flux calibration becomes ambiguous. Therefore, we elect to transform the corrected data onto the HST FOS system. This system is far more self-consistent, and transforming the IUE data to it places data from both telescopes on a single system. Finally, we argue that much of the remaining 3% systematic effects in the corrected data is traceable to problems with the NEWSIPS intensity transformation function (ITF). The accuracy could probably be doubled by rederiving the ITF.Comment: Submitted to ApJ Supplement, 35 pages, 13 figures, LaTeX - AASTEX aas2pp4.st

Una Aproximació a l'obra d'Aristarc de Samos (ca. 310 aC - 230 aC)

Aristarchus, known as the ancient Copernicus by his heliocentric ideas, was the author of the work: «On the sizes and distances of the Sun and Moon». In this text Aristarchus could be seem as a pioneer of Greek astronomy. He reckoned the sizes of the Sun and the Moon and compared them with the Earth and the distances of these asters to the Earth. After the publication of my Spanish translation of this text (2007), the aim of this paper is to provide some mathematical features deduced from the analysis of the work of Aristarchus

Jaume Balmes: notes i escrits matemàtics

Jaume Balmes (1810-1848), conegut com a filòsof i com a publicista catòlic, va exercir durant quatre anys (1837-1841) com a professor de matemàtiques a la Càtedra de Matemàtiques de Vic. Encara que la bibliografia sobre Balmes i les seves obres és molt nombrosa, hi ha pocs textos que es refereixin específicament a l’aspecte matemàtic. En aquest article ens proposem analitzar algunes idees matemàtiques de Balmes tant pel que fa a la seva creença en la matemàtica com a base de progrés, com a la part més teòrica a la qual va contribuir amb els seus escrits.Postprint (published version

La Història de les matemàtiques dins dels nous currículums de secundària

The new Catalan curriculum of mathematics to Secondary Compulsory Education contents some suggestions to use history of mathematics to teach mathematics. In this paper we present a proposal for training history context in mathematical lessons and we also illustrate it with an example concerning to 3rd year in the official curriculum: solving equations in Arabian World