6,686 research outputs found
Constraining the Milky Way Dark Matter Density Profile with Gamma-Rays with Fermi-LAT
We study the abilities of the Fermi-LAT instrument on board of the Fermi
mission to simultaneously constrain the Milky Way dark matter density profile
and some dark matter particle properties, as annihilation cross section, mass
and branching ratio into dominant annihilation channels. A single dark matter
density profile is commonly assumed to determine the capabilities of gamma-ray
experiments to extract dark matter properties or to set limits on them.
However, our knowledge of the Milky Way halo is far from perfect, and thus in
general, the obtained results are too optimistic. Here, we study the effect
these astrophysical uncertainties would have on the determination of dark
matter particle properties and conversely, we show how gamma-ray searches could
also be used to learn about the structure of the Milky Way halo, as a
complementary tool to other type of observational data that study the
gravitational effect caused by the presence of dark matter. In addition, we
also show how these results would improve if external information on the
annihilation cross section and on the local dark matter density were included
and compare our results with the predictions from numerical simulations.Comment: 29 pages, 7 figure
Strict calculation of the light statistics at the output of a travelling wave optical amplifier
A new method for calculating the probability density function of the photon number propagating through a travelling wave optical amplifier with no restriction on its working regime (linear and nonlinear) is reported. The authors show that the widely used Gaussian approximation of the probability density function does not match the real statistics if the incident optical power is small.Peer ReviewedPostprint (published version
lo obsceno como escena
La escena se desplaza a lo obsceno y viceversa. Diferentes ejemplos de la cultura visual en su relación con la puesta en escena y desnudo obsceno. La estética a través de lo escatológico
Practical method for modelling the nonlinear behaviour of a travelling wave semiconductor optical amplifier
The authors present a simple model of a travelling wave semiconductor optical amplifier with an appreciable degree of saturation. The model uses a particular way of linearising the total carrier recombination R(N) to find useful expressions for the saturation parameter and/or the carrier lifetime. By combining these expressions and the gain measurements realised, it is possible to establish the dependence between the mentioned parameters and the input optical power.Peer ReviewedPostprint (published version
WMT 2016 Multimodal translation system description based on bidirectional recurrent neural networks with double-embeddings
Bidirectional Recurrent Neural Networks (BiRNNs) have shown outstanding results on sequence-to-sequence learning tasks. This architecture becomes specially interesting for multimodal machine translation task, since BiRNNs can deal with images and text. On most translation systems the same word embedding is fed to both BiRNN units. In this paper, we present several experiments to enhance a baseline sequence-to-sequence system (Elliott et al., 2015), for example, by using double embeddings. These embeddings are trained on the forward and backward direction of the input sequence. Our system is trained, validated and tested on the Multi30K dataset (Elliott et al., 2016) in the context of theWMT 2016Multimodal Translation Task. The obtained results show that thedouble-embedding approach performs significantly better than the traditional single-embedding one.Postprint (published version
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