Web-Based Visualization of Very Large Scientific Astronomy Imagery

Visualizing and navigating through large astronomy images from a remote location with current astronomy display tools can be a frustrating experience in terms of speed and ergonomics, especially on mobile devices. In this paper, we present a high performance, versatile and robust client-server system for remote visualization and analysis of extremely large scientific images. Applications of this work include survey image quality control, interactive data query and exploration, citizen science, as well as public outreach. The proposed software is entirely open source and is designed to be generic and applicable to a variety of datasets. It provides access to floating point data at terabyte scales, with the ability to precisely adjust image settings in real-time. The proposed clients are light-weight, platform-independent web applications built on standard HTML5 web technologies and compatible with both touch and mouse-based devices. We put the system to the test and assess the performance of the system and show that a single server can comfortably handle more than a hundred simultaneous users accessing full precision 32 bit astronomy data.Comment: Published in Astronomy & Computing. IIPImage server available from http://iipimage.sourceforge.net . Visiomatic code and demos available from http://www.visiomatic.org

The potential-energy tensors for subsystems. IV. Homeoidally striated density profiles with a central cusp

A general theory of homeoidally striated density profiles where no divergence occurs, is adapted to cuspy density profiles, with a suitable choice of the scaling density and the scaling radius. A general formulation of some physical parameters, such as angular-momentum vector, rotational-energy tensor (both calculated in connection with a special class of rotational velocity fields), inertia tensor, and self potential-energy tensor, is performed. Other potential-energy tensors involving two density profiles where the boundaries are similar and similarly placed, are also expressed. Explicit results are attained for three special cases of physical interest which fit to a good extent the results of high-resolution simulations for dark matter haloes, and a class of density profiles, which closely approximate the de Vaucouleurs $r^{1/4}$ law for elliptical galaxies. The virial theorem in tensor form for two-component systems is written for each subsystem, and applied to giant elliptical galaxies. The predicted velocity dispersion along the line of sight, in the limiting case where a principal axis points towards the observer, is found to be consistent with observations except for (intrinsic) $E7$ configurations where the major axis points towards the observer. If dark matter haloes host an amount of undetected baryons about twice as massive as the stellar subsystem, and undetected baryons trace non baryonic matter therein, two main consequences arise, namely (i) velocity dispersions along the line of sight are lower than in absence of undetected baryons, and (ii) dark matter haloes are dynamically ``hotter'' than stellar ellipsoids, the transition occurring when the amount of undetected baryons is about one and a half times that of the stellar subsystem.Comment: New Astronomy, accepte

Application of Scenedesmus obliquus in the Treatment of a Real Wastewater

In the present study, the microalga Scenedesmus obliquus CCAP 276/38 has been applied in the treatment of a real wastewater (RWW) derived from an anaerobic digestion process of corn silage and livestock wastewater. The liquid phase of the digestate showed a low viscosity value and a high content of ammonia up to 3 g/L. In a preliminary phase, the experimental tests were carried out in Erlenmeyer flasks in order to identify the optimal RWW concentration and, in particular, its influence on biomass growth and productivity. The tests were carried out at 20°C at an artificial dark/light cycles of 12 hours. Three different concentrations were tested: 1, 2 and 3% of RWW in water, in the presence of sodium bicarbonate (NaHCO3, 50 mM) as inorganic carbon source. The obtained results showed that S. obliquus was able to grow in all the tested RWW concentrations even if a higher growth rate and biomass production were observed in the cultures containing 1% RWW. In order to test the influence of N/P ratio on microalgal growth, two different salts, KNO3 (0,2 g/L) and K2HPO4 (0,02 g/L), were added to the medium containing 1% RWW (N/P = 84.4), to correct the N/P value. The biomass growth rate increased in the medium with the lower N/P value (N/P = 27.9). The microalgal production process was scaled-up in a stirred tank photobioreactor (working volume 5 L), in the same temperature and illumination conditions using a medium with the composition optimized in flask tests. The culture was carried out for 124 hours, fed-batch addition of RWW (1%) was done during the fermentation in order to replace the carbon source. The results (growth rate, biomass dry weight and productivity) were compared with those obtained in presence of a synthetic medium with sodium bicarbonate 50 mM as carbon source. The work clearly demonstrated the capability of S. obliquus CCAP 276/38to grow in alkaline wastewater and the possibility to employ this species in the treatment of effluents containing high ammonia concentratio

Development of a Planetary Web GIS at the ''Photothèque Planétaire'' in Orsay

International audienceThe "Photothèque Planétaire d'Orsay" belongs to the Regional Planetary Image Facilities (RPIF) network started by NASA in 1984. The original purpose of the RPIF was mainly to provide easy access to data from US space missions throughout the world. The "Photothèque" itself specializes in planetary data processing and distribution for research and public outreach. Planetary data are heterogeneous, and combining different observations is particularly challenging, especially if they belong to different data-sets. A common description framework is needed, similar to the existing Geographical Information Systems (GIS) that have been developed for manipulating Earth data. In their present state, GIS software and standards cannot directly be applied to other planets because they still lack flexibility in managing coordinate systems. Yet, the GIS framework serves as an excellent starting point for the implementation of a Virtual Observatory for Planetary Sciences, provided it is made more generic and inter-operable. The "Photothèque Planétaire d'Orsay" has produced some planetary GIS examples using historical and public data-sets. Our main project is a Web-based visualization system for planetary data, which features direct point-and-click access to quantitative measurements. Thanks to being compatible with all recent web browsers, our interface can also be used for public outreach and to make data accessible for education and training

Development of a Planetary Web GIS at the ''Photothèque Planétaire'' in Orsay

International audienceThe "Photothèque Planétaire d'Orsay" belongs to the Regional Planetary Image Facilities (RPIF) network started by NASA in 1984. The original purpose of the RPIF was mainly to provide easy access to data from US space missions throughout the world. The "Photothèque" itself specializes in planetary data processing and distribution for research and public outreach. Planetary data are heterogeneous, and combining different observations is particularly challenging, especially if they belong to different data-sets. A common description framework is needed, similar to the existing Geographical Information Systems (GIS) that have been developed for manipulating Earth data. In their present state, GIS software and standards cannot directly be applied to other planets because they still lack flexibility in managing coordinate systems. Yet, the GIS framework serves as an excellent starting point for the implementation of a Virtual Observatory for Planetary Sciences, provided it is made more generic and inter-operable. The "Photothèque Planétaire d'Orsay" has produced some planetary GIS examples using historical and public data-sets. Our main project is a Web-based visualization system for planetary data, which features direct point-and-click access to quantitative measurements. Thanks to being compatible with all recent web browsers, our interface can also be used for public outreach and to make data accessible for education and training

Universal density profiles with a central cusp

Grounding on both theoretical predictions and observational evidences, gas and stars contribute to about one tenth of the total mass of galaxies, and are lying within a more extended subsystem made of some (still unspecified) dark matter. The knowledge of the density profile of such dark matter halos is important, in that it influences the contraction of the baryonic subsystem, and then the structure of the virialized galaxy. In the current attempt, the general theory of realistic density profiles is performed, and explicit expressions of some physical parameters are derived. We are interested in triaxial, ellipsoidal structures where the isodensity surfaces are similar and co-axial ellipsoids