Repeated X-ray Flaring Activity in Sagittarius A*

Investigating the spectral and temporal characteristics of the X-rays coming from Sagittarius A* (Sgr A*) is essential to our development of a more complete understanding of the emission mechanisms in this supermassive black hole located at the center of our Galaxy. Several X-ray flares with varying durations and spectral features have already been observed from this object. Here we present the results of two long XMM-Newton observations of the Galactic nucleus carried out in 2004, for a total exposure time of nearly 500 ks. During these observations we detected two flares from Sgr A* with peak 2-10 keV luminosities about 40 times (L ~ 9x10^34 erg s−1) above the quiescent luminosity: one on 2004 March 31 and another on 2004 August 31. The first flare lasted about 2.5 ks and the second about 5 ks. The combined fit on the Epic spectra yield photon indeces of about 1.5 and 1.9 for the first and second flare respectively. This hard photon index strongly suggests the presence of an important population of non-thermal electrons during the event and supports the view that the majority of flaring events tend to be hard and not very luminous.Comment: 8 pages, 7 figures, Accepted for publication in the Astrophysical Journa

A vision-based assistance key differenciator for helicopters automonous scalable missions

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Contribution of point sources to the soft gamma-ray Galactic emission

The nature of the soft gamma-ray (20-200 keV) Galactic emission has been a matter of debate for a long time. Previous experiments have tried to separate the point source contribution from the real interstellar emission, but with a rather poor spatial resolution, they concluded that the interstellar emission could be a large fraction of the total Galactic emission. INTEGRAL, having both high resolution and high sensitivity, is well suited to reassess more precisely this problem. Using the INTEGRAL core program Galactic Center Deep Exposure (GCDE), we estimate the contribution of detected point sources to the total Galactic flux.Comment: Proceedings of the 5th INTEGRAL Workshop, Munich 16-20 February 2004. ESA SP-55

Probing the Density in the Galactic Center Region: Wind-Blown Bubbles and High-Energy Proton Constraints

Recent observations of the Galactic center in high-energy gamma-rays (above 0.1TeV) have opened up new ways to study this region, from understanding the emission source of these high-energy photons to constraining the environment in which they are formed. We present a revised theoretical density model of the inner 5pc surrounding Sgr A* based on the fact that the underlying structure of this region is dominated by the winds from the Wolf-Rayet stars orbiting Sgr A*. An ideal probe and application of this density structure is this high energy gamma-ray emission. We assume a proton-scattering model for the production of these gamma-rays and then determine first whether such a model is consistent with the observations and second whether we can use these observations to further constrain the density distribution in the Galactic center.Comment: 36 pages including 17 figures, submitted to ApJ, comments welcom

Embedding intelligent image processing algorithms : the new safety enhancer for helicopters missions

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Intercomparison of timothy models in northern countries

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Intercomparison of models for simulating timothy yield in northern countries

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Demographic Scenarios for the EU

Over the recent decades, the EU has been shaped by population growth, but now its population is ageing. Together with North America and East Asia, the EU is moving towards longer-living, lower-fertility, and higher-educated societies. Facing this new demographic frontier naturally prompts the questions: Who will live and work in Europe in the coming decades? How many, and with what skills? To answer these, this report examines the key factors that will shape European demographics over the coming decades. By examining not only the role of migration, fertility and mortality, but also education levels and labour force participation rates, a more comprehensive view of possible futures can be outlined than the conventional demographic projections allow for. The first five sections of this report focus on demographic challenges inside the EU, such as population ageing, a shrinking labour force, more non-working people being dependent on working people, and showing the impact of high levels of emigration in some EU Member States. With these challenges in mind and with a view towards 2060, the report builds scenarios to understand the long-term effects of changes in key trends, and whether undesirable consequences can be limited or counteracted. As the EU and its demographics do not exist in isolation, the following sections explore the relevant trends for world demographics and for migration flows.JRC.A.5-Scientific Developmen