4 research outputs found
Industrial Infrastructure: Translocal Planning for Global Production in Ethiopia and Argentina
Current development and re-development of industrial areas cannot be adequately understood without taking into account the organisational structures and logistics of commodity production on a planetary scale. Global production networks contribute not only to the reconfiguration of urban spatial and economic structures in many places, but they also give rise to novel transnational actor constellations, thus reconfiguring planning processes. This article explores such constellations and their urban outcomes by investigating two current cases of industrial development linked with multilateral transport-infrastructure provisioning in Ethiopia and Argentina. In both cases, international partners are involved, in particular with stakeholders based in China playing significant roles. In Mekelle, Ethiopia, we focus on the establishment of a commodity hub through the implementation of new industry parks for global garment production and road and rail connections to international seaports. In the Rosario metropolitan area in Argentina, major cargo rail and port facilities are under development to expand the countryâs most important ports for soybean export. By mapping the physical architectures of the industrial and infrastructure complexes and their urban contexts and tracing the translocal actor constellations involved in infrastructure provisioning and operation, we analyse the spatial impacts of the projects as well as the related implications for planning governance. The article contributes to emergent scholarship and theorisations of urban infrastructure and global production networks, as well as policy mobility and the transnational constitution of planning knowledge and practices
Dark Energy Survey year 3 results: covariance modelling and its impact on parameter estimation and quality of fit
We describe and test the fiducial covariance matrix model for the combined two-point function analysis of the Dark Energy Survey Year 3 (DES-Y3) data set. Using a variety of new ansatzes for covariance modelling and testing, we validate the assumptions and approximations of this model. These include the assumption of Gaussian likelihood, the trispectrum contribution to the covariance, the impact of evaluating the model at a wrong set of parameters, the impact of masking and survey geometry, deviations from Poissonian shot noise, galaxy weighting schemes, and other sub-dominant effects. We find that our covariance model is robust and that its approximations have little impact on goodness of fit and parameter estimation. The largest impact on best-fitting figure-of-merit arises from the so-called fsky approximation for dealing with finite survey area, which on average increases the Ï2 between maximum posterior model and measurement by 3.7 per cent (ÎÏ2 â 18.9). Standard methods to go beyond this approximation fail for DES-Y3, but we derive an approximate scheme to deal with these features. For parameter estimation, our ignorance of the exact parameters at which to evaluate our covariance model causes the dominant effect. We find that it increases the scatter of maximum posterior values for Ωm and Ï8 by about 3 per cent and for the dark energy equation-of-state parameter by about 5 per centâ
The DES view of the Eridanus supervoid and the CMB cold spot
ABSTRACT
The Cold Spot is a puzzling large-scale feature in the Cosmic Microwave Background temperature maps and its origin has been subject to active debate. As an important foreground structure at low redshift, the Eridanus supervoid was recently detected, but it was subsequently determined that, assuming the standard ÎCDM model, only about 10â20 per cent of the observed temperature depression can be accounted for via its Integrated SachsâWolfe imprint. However, R âł 100 hâ1Mpc supervoids elsewhere in the sky have shown ISW imprints AISW â 5.2 ± 1.6 times stronger than expected from ÎCDM (AISW = 1), which warrants further inspection. Using the Year-3 redMaGiC catalogue of luminous red galaxies from the Dark Energy Survey, here we confirm the detection of the Eridanus supervoid as a significant underdensity in the Cold Spotâs direction at z < 0.2. We also show, with S/N âł 5 significance, that the Eridanus supervoid appears as the most prominent large-scale underdensity in the dark matter mass maps that we reconstructed from DES Year-3 gravitational lensing data. While we report no significant anomalies, an interesting aspect is that the amplitude of the lensing signal from the Eridanus supervoid at the Cold Spot centre is about 30 per cent lower than expected from similar peaks found in N-body simulations based on the standard ÎCDM model with parameters Ωm = 0.279 and Ï8 = 0.82. Overall, our results confirm the causal relation between these individually rare structures in the cosmic web and in the CMB, motivating more detailed future surveys in the Cold Spot region
Dark Energy Survey Year 3 results: Curved-sky weak lensing mass map reconstruction
ABSTRACT
We present reconstructed convergence maps, mass maps, from the Dark Energy Survey (DES) third year (Y3) weak gravitational lensing data set. The mass maps are weighted projections of the density field (primarily dark matter) in the foreground of the observed galaxies. We use four reconstruction methods, each is a maximum a posteriori estimate with a different model for the prior probability of the map: KaiserâSquires, null B-mode prior, Gaussian prior, and a sparsity prior. All methods are implemented on the celestial sphere to accommodate the large sky coverage of the DES Y3 data. We compare the methods using realistic ÎCDM simulations with mock data that are closely matched to the DES Y3 data. We quantify the performance of the methods at the map level and then apply the reconstruction methods to the DES Y3 data, performing tests for systematic error effects. The maps are compared with optical foreground cosmic-web structures and are used to evaluate the lensing signal from cosmic-void profiles. The recovered dark matter map covers the largest sky fraction of any galaxy weak lensing map to date