4,940 research outputs found
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
Jaume Balmes: notes i escrits matemĂ tics
Jaume Balmes (1810-1848), conegut com a
filòsof i com a publicista catòlic, va exercir
durant quatre anys (1837-1841) com a
professor de matemĂ tiques a la CĂ tedra de
MatemĂ tiques de Vic. Encara que la bibliografia
sobre Balmes i les seves obres Ă©s molt
nombrosa, hi ha pocs textos que es refereixin
especĂficament a l’aspecte matemĂ tic.
En aquest article ens proposem analitzar
algunes idees matemĂ tiques de Balmes tant
pel que fa a la seva creença en la matemà tica
com a base de progrés, com a la part
més teòrica a la qual va contribuir amb els
seus escrits.Postprint (published version
Una AproximaciĂł 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
La Història de les matemĂ tiques dins dels nous currĂculums de secundĂ ria
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
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