An original interferometric study of NGC 1068 with VISIR BURST mode images

We present 12.8 microns images of the core of NGC 1068 obtained with the BURST mode of the VLT/VISIR. We trace structures under the diffraction limit of one UT and we investigate the link between dust in the vicinity of the central engine of NGC 1068, recently resolved by interferometry with MIDI, and more extended structures. This step is mandatory for a multi-scale understanding of the sources of mid-infrared emission in AGNs. A speckle processing of VISIR BURST mode images was performed to extract very low spatial-frequency visibilities, first considering the full field of VISIR BURST mode images and then limiting it to the mask used for the acquisition of MIDI data. Extracted visibilities are reproduced with a multi-component model. We identify two major sources of emission: one compact < 85 mas, associated with the dusty torus, and an elliptical one, (< 140) mas x 1187 mas at P.A.=-4 degrees from N to E. This is consistent with previous deconvolution processes. The combination with MIDI data reveals the close environment of the dusty torus to contribute to about 83 percent of the MIR flux seen by MIDI. This strong contribution has to be considered in modeling long baseline interferometric data. It must be related to the NS elongated component which is thought to originate from individually unresolved dusty clouds and is located inside the ionization cone. Low temperatures of the dusty torus are not challenged, emphasizing the scenarios of clumpy torus.Comment: 10 pages, 7 figures, accepted for publication in A&

Les Organisations de la Société Civile et la Lutte Contre la Pauvreté en Afrique Subsaharienne

The paper presents the role played by civil society organisations to bring down the poverty

Exploring high repetitivity remote sensing time series for mapping and monitoring natural habitats ; A new approach combining OBIA and k-partite graphs

International audienc

Ammonia (J,K) = (1,1) to (4,4) and (6,6) inversion lines detected in the Seyfert 2 galaxy NGC 1068

We present the detection of the ammonia (NH3) (J,K) = (1,1) to (4,4) and (6,6) inversion lines toward the prototypical Seyfert 2 galaxy NGC 1068, made with the Green Bank Telescope (GBT). This is the first detection of ammonia in a Seyfert galaxy. The ortho-to-para-NH3 abundance ratio suggests that the molecule was formed in a warm medium of at least 20 K. For the NH3 column density and fractional abundance, we find (1.09\pm0.23)\times10^14 cm^-2 and (2.9\pm0.6)\times10^-8, respectively, from the inner 1.2 kpc of NGC 1068. The kinetic temperature can be constrained to 80\pm20 K for the bulk of the molecular gas, while some fraction has an even higher temperature of 140\pm30 K.Comment: 5 pages, 3 figures, accepted by A&

On the effective shear speed in 2D phononic crystals

The quasistatic limit of the antiplane shear-wave speed ('effective speed') $c$ in 2D periodic lattices is studied. Two new closed-form estimates of $c$ are derived by employing two different analytical approaches. The first proceeds from a standard background of the plane wave expansion (PWE). The second is a new approach, which resides in $\mathbf{x}$-space and centers on the monodromy matrix (MM) introduced in the 2D case as the multiplicative integral, taken in one coordinate, of a matrix with components being the operators with respect to the other coordinate. On the numerical side, an efficient PWE-based scheme for computing $c$ is proposed and implemented. The analytical and numerical findings are applied to several examples of 2D square lattices with two and three high-contrast components, for which the new PWE and MM estimates are compared with the numerical data and with some known approximations. It is demonstrated that the PWE estimate is most efficient in the case of densely packed stiff inclusions, especially when they form a symmetric lattice, while in general it is the MM estimate that provides the best overall fitting accuracy.Comment: 13 pages, 9 figure

Marker-Assisted Pyramiding of Blast-Resistance Genes in a japonica Elite Rice Cultivar through Forward and Background Selection

Rice blast, caused by Pyricularia oryzae, is one of the main rice diseases worldwide. The pyramiding of blast-resistance (Pi) genes, coupled to Marker-Assisted BackCrossing (MABC), provides broad-spectrum and potentially durable resistance while limiting the donor genome in the background of an elite cultivar. In this work, MABC coupled to foreground and background selections based on KASP marker assays has been applied to introgress four Pi genes (Piz, Pib, Pita, and Pik) in a renowned japonica Italian rice variety, highly susceptible to blast. Molecular analyses on the backcross (BC) lines highlighted the presence of an additional blast-resistance gene, the Pita-linked Pita2/Ptr gene, therefore increasing the number of blast-resistance introgressed genes to five. The recurrent genome was recovered up to 95.65%. Several lines carrying four (including Pita2) Pi genes with high recovery percentage levels were also obtained. Phenotypic evaluations confirmed the effectiveness of the pyramided lines against multivirulent strains, which also had broad patterns of resistance in comparison to those expected based on the pyramided Pi genes. The developed blast-resistant japonica lines represent useful donors of multiple blast-resistance genes for future rice-breeding programs related to the japonica group

Damage Detection Using Blind Source Separation Techniques

Blind source separation (BSS) techniques are applied in many domains since they allow separating a set of signals from their observed mixture without the knowledge (or with very little knowledge) of the source signals or the mixing process. Two particular BSS techniques called Second-Order Blind Identification (SOBI) and Blind Modal Identification (BMID) are considered in this paper for the purpose of structural damage detection or fault diagnosis in mechanical systems. As shown on experimental examples, the BMID method reveals significant advantages. In addition, it is demonstrated that damage detection results may be improved significantly with the help of the block Hankel matrix. The main advantage in this case is that damage detection still remains possible when the number of available sensors is small or even reduced to one. Damage detection is achieved by comparing the subspaces between the reference (healthy) state and a current state through the concept of subspace angle. The efficiency of the methods is illustrated using experimental data