726 research outputs found
The Faint Sky Variability Survey I: Goals and data reduction process
The Faint Sky Variability Survey is aimed at finding photometric and/or
astrometric variable objects in the brightness range between 16<V<24 on
timescales between tens of minutes and years with photometric precisions
ranging from 3 millimagnitudes for the brightest to 0.2 magnitudes for the
faintest objects. An area of ~23 square degrees, located at mid and high
Galactic latitudes, has been covered using the Wide Field Camera on the 2.5m
Isaac Newton Telescope on La Palma. Here we describe the main goals of the
Faint Sky Variability Survey and the data reduction process.Comment: Accepted by MNRAS, 8 pages, 6 figure + 3 as JPEG
What fraction of stars formed in infrared galaxies at high redshift?
Star formation happens in two types of environment: ultraviolet-bright
starbursts (like 30 Doradus and HII galaxies at low redshift and Lyman-break
galaxies at high redshift) and infrared-bright dust-enshrouded regions (which
may be moderately star-forming like Orion in the Galaxy or extreme like the
core of Arp 220). In this work I will estimate how many of the stars in the
local Universe formed in each type of environment, using observations of
star-forming galaxies at all redshifts at different wavelengths and of the
evolution of the field galaxy population.Comment: 7 pages, 0 figs, to appear in proceedings of "Starbursts - From 30
Doradus to Lyman break galaxies", edited by Richard de Grijs and Rosa M.
Gonzalez Delgado, published by Kluwe
Inference from controversial arguments
International audienceWe present new careful semantics within Dung's theory of argumentation. Under such careful semantics, two arguments cannot belong to the same extension whenever one of them indirectly attacks a third argument while the other one indirectly defends the third.We argue that our semantics lead to a better handling of controversial arguments than Dung's ones in some settings. We compare the careful inference relations induced by our semantics w.r.t. cautiousness; we also compare them with the inference relations induced by Dung's semantic
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