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Giulio Fabbian

Dr Giulio Fabbian

Marie Curie Fellow

School of Physics and Astronomy


I am a cosmologist interested in studying open problems in fundamental physics and astrophysics with observations of the Cosmic Microwave Background and of the large-scale structures of the universe via the gravitational lensing effect.

I hold a joint position at Cardiff and at the Center for Computational Astrophysics of the Flatiron Institute in New York.






My research lies at the interface between computer science, experimental physics and theoretical cosmology.

I am interested in developing new theoretical understanding of cosmological observables, as well as data analysis and numerical simulation techniques to analyze astrophysical data. To accurately understand our data, we need to learn the properties of our instruments, and I am an expert in connecting instrumental systematic effects with final cosmolgical measurements.

These days I am particularly interested in synergies between observations of the sky in the microwave band and galaxy surveys in other frequencies. I am keen to combine these two data sets to improve our knowledge of the universe and shed light on neutrino physics, inflation, dark matter and dark energy as well as on a variety of galactic and extragalactic astrophysics (e.g. the physics of galaxy clusters or IGM).

I am a member of multiple CMB experiments. I started my career working on the POLARBEAR experiment, a telescope dedicated to CMB observations that produced the first measurement of its elusive B-mode polarization patter imprinted by the gravitational lensing effect. Since then I became part of the Simons Observatory and CMB-S4 collaboration.

I co-lead the lensing working group of Simons Observatory and in particular the cross-correlation science with galaxy surveys. I am also part of the Euclid consortium where I co-lead similar activities in its dedicated science working group.



  • 2021-present Marie Skłodowska Curie Global Fellow, Center for Computational Astrophysics at the Flatiron Institute (New York, USA) and Cardiff University.
  • 2018-2020 Research Fellow, University of Sussex.
  • 2016–2018 CNES postdoctoral fellow, Institut d’Astrophysique Spatiale (IAS), Orsay, France.
  • 2013–2016 Postdoctoral Fellow, International School for Advanced Studies (SISSA), Trieste, Italy.

Visiting positions

  • 02/2020 Visiting researcher, CERN Theory division, Geneva, CH.
  • 10-11/2015 Visiting Sciama Legacy Fellow, Department of Applied Mathematics and Theoretical Physics (DAMTP), University of Cambridge, Cambridge, UK.
  • 01/2011 Visiting graduate student, Computational Cosmology Center, Lawrence Berkeley National Laboratory (LBNL), Berkeley, USA.


  • 2010-2013 PhD in Physics, University of Paris VII Denis Diderot, awarded with distinctions. Advisor: Dr. Radek Stompor.
  • 2008-2010 Msc in Astrophysics and Space Science, University of Milano-Bicocca, Milan, Italy, Grade 110/110.
  • 2009: International Exchange Programme Student, Ecole Polytechnique, Palaiseau, France.
  • 2005-2008 Bsc in Physics, University of Milano-Bicocca, Milan, Italy.

Honours and awards

  • 2020 Marie Skłodowska Curie Global Fellowship project n. 892401 Precision Cosmology with Galaxy and Microwave Background Surveys (PiCOGAMBAS).
  • 2019 STFC Consolidated grant (w/ Prof. A. Lewis).
  • 2016 CNES postdoctoral fellowship.
  • 2015 Dennis Sciama Legacy Fellowship.
  • 2010 ExTRA fellowship of the CARIPLO foundation.

Committees and reviewing

  • Reviewing
    • Referee Physical Review Letters, Physical Review D, JCAP, Astronomy & Astrophysics, The Astrophysical Journal.
    • Grant reviewer for Japan Society for the Promotion of Science (JSPS).
    • Phd reviewer for University of Paris 11.
    • Internal reviewer of collaboration papers for CMB-S4, Simons Observatory, POLARBEAR

  • Committees
    • 2020 Organizer of the CMB lensing workshop (University of Sussex).
    • 2019 Organizer of the South Coast Cosmology meeting (University of Sussex )2018 Organizer of the Euclid CMB - cross-correlation SWG meeting
    • 2012 Member of the organizing committee of the "Big3: Big bang, Big data, Big computers" conference (Paris, France). Organizer of the Euclid CMB - cross-correlation SWG meeting (Orsay, France, 2018).