I am also an active member of the Euclid Consortium, where I co-lead the Weak Lensing Science Working Group. My academic path began with a PhD at the Max Planck Institute for Astrophysics, where I developed methods to map the mass distribution of the Universe from quasar spectra (the Lyman-alpha forest) and designed Bayesian tools to address unknown systematics in galaxy clustering surveys. After my PhD, I worked as a postdoctoral researcher at Imperial College London and later as a Beecroft Fellow at the University of Oxford. In December 2025, I moved to the CEA Irfu and joined the Cosmostat group.
I am also an active member of the Euclid Consortium, where I co-lead the Weak Lensing Science Working Group. My academic path began with a PhD at the Max Planck Institute for Astrophysics, where I developed methods to map the mass distribution of the Universe from quasar spectra (the Lyman-alpha forest) and designed Bayesian tools to address unknown systematics in galaxy clustering surveys. After my PhD, I worked as a postdoctoral researcher at Imperial College London and later as a Beecroft Fellow at the University of Oxford. In December 2025, I moved to the CEA Irfu and joined the Cosmostat group.
I am a permanent researcher in the Cosmostat group at CEA Paris-Saclay, where I develop new methods to analyse data from cosmological surveys. My research aims to make an optimal use of weak lensing observations to investigate dark energy, dark matter, and the formation of cosmic structures. I am the principal investigator of the OCAPi project (starting in 2026), funded by an ERC Starting Grant, which analyses weak lensing maps at the pixel level. This novel approach improves the precision of cosmological parameter constraints and provides a map of the matter distribution in the Universe, effectively making the dark matter visible.​​
Natalia Porqueres
I am also an active member of the Euclid Consortium, where I co-lead the Weak Lensing Science Working Group. My academic path began with a PhD at the Max Planck Institute for Astrophysics, where I developed methods to map the mass distribution of the Universe from quasar spectra (the Lyman-alpha forest) and designed Bayesian tools to address unknown systematics in galaxy clustering surveys. After my PhD, I worked as a postdoctoral researcher at Imperial College London and later as a Beecroft Fellow at the University of Oxford. In December 2025, I moved to the CEA Irfu and joined the Cosmostat group.
Publications
OCAPi: Optimal Cosmological Analysis at the Pixel level.
The standard cosmological model succeeds at explaining a vast range of observations, but it relies on two components we still do not understand: dark matter and dark energy. To investigate their nature, the Euclid mission and the Vera C. Rubin Observatory will measure the positions and shapes of billions of galaxies. The apparent shapes of galaxies are slightly distorted by the gravity of cosmic structures, an effect known as weak gravitational lensing. This is the most promising cosmological probe of the next decade, and, combined with the unprecedented precision of Euclid and Rubin, can revolutionise our understanding of the Universe. However, realising the full potential of these datasets will require highly precise and accurate data analysis techniques.
The OCAPi project will develop cutting-edge methods to make optimal use of weak lensing data and deliver the most precise constraints on cosmological parameters from Euclid data. Unlike standard analyses, which compress the data and inevitably lose information, OCAPi will analyse the lensing maps pixel by pixel, without any data compression. This ensures that we capture all the information in the data, maximising precision and strengthening our ability to distinguish cosmological signals from systematic effects. This approach also provides probabilistic maps of the matter distribution at different cosmic times, making dark matter visible and opening up a new way of testing physics with the large-scale structures of the Universe.
By maximising the scientific return of one of the most powerful datasets that cosmology will have for decades, OCAPi will advance our understanding of dark energy and provide a digital twin of the Universe to investigate the formation and evolution of cosmic structures.
Contact
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Department of Astrophysics,
IRFU, CEA Saclay
Orme des Merisiers, Bat 709
91191 Gif-sur-Yvette
France