Speaker
Description
The new generation radio telescopes, such as the Square Kilometre Array (SKA), are expected to reach sufficient sensitivity and resolution to provide large number densities of resolved faint sources, and therefore to open weak gravitational lensing observations to the radio band. In this talk I will present RadioLensfit, an open-source tool for an efficient and fast galaxy shape measurement for radio weak lensing shear. It performs a single source model fitting in the Fourier domain, after isolating the source visibilities with a sky model and a faceting technique. This approach makes real sized radio datasets accessible to an analysis in this domain, where data is not yet affected by the systematics introduced by the non-linear imaging process. The code is also able to exploit multi-node HPC infrastructures by a hybrid parallelization MPI+OpenMP for accelerating the computation and dealing with very large datasets, that possibly cannot entirely be stored in the memory of a single processor. Using SKA-MID simulated datasets, I will present performance results both in terms of code scalability and measurement accuracy at the expected SKA1 source density, showing that results are comparable with a joint fitting approach but with a computational time highly reduced. Finally I will discuss the work that is on-going with the data of the UK e-MERLIN legacy project SuperCLASS, a precursor weak lensing survey performed combining the SKA pathfinder telescopes e-MERLIN and JVLA.
| Reasearch area | Cosmology |
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