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Kavli Institute for Cosmology, Cambridge


Sandro Tacchella is an astrophysicist working at the Department of Physics (Cavendish Laboratory) and at the Kavli Institute for Cosmology of the University of Cambridge. Before joining the University of Cambridge in 2022, he was Assistant Professor at the Physics Department of UNIST in Ulsan, Korea. From 2017-2021, he was a CfA Fellow at the Harvard-Smithsonian Center for Astrophysics in Cambridge, USA. He has received his Ph.D. from ETH Zurich (Switzerland) in 2017.

Sandro's long-range scientific goal is to understand the physics of the formation and evolution of galaxies and black holes across cosmic time. Specifically, he investigates the physical mechanisms that govern the formation of the first galaxies in the early universe, the buildup of the bulge and disk components in galaxies, and the cessation of star formation in massive galaxies. He exploits cutting-edge multi-wavelength observational data obtained with some of the most advanced telescopes on ground and in space. He uses and develops analytical and cosmological numerical models to shed light on the physical properties of galaxies. Sandro is also heavily involved in the new James Webb Space Telescope, playing a key role both in the data processing of the NIRCam instrument and in projects aimed at detecting galaxies formed in the early Universe and at characterising their primeval properties.


  • 2022-present: Assistant Professor, Cavendish Laboratory (Department of Physics) & Kavli Institute for Cosmology, University of Cambridge, UK
  • 2021-2022: Assistant Professor, Department of Physics, UNIST, Korea
  • 2017-2021: CfA Fellow, Harvard-Smithsonian Center for Astrophysics, USA
  • 2012-2017: Ph. D. in Physics, ETH Zurich, Switzerland
  • 2010-2012: M. Sc. in Physics, ETH Zurich, Switzerland
  • 2007-2010: B. Sc. in Physics, ETH Zurich, Switzerland


  • Extragalactic astrophysics & observational cosmology
  • Observational and theoretical studies of galaxy formation and evolution
  • Interplay between baryons, dark matter and black holes
  • Observations of distant galaxies with the most advanced telescopes
  • Development and analysis of analytical and numerical models of galaxy formation
  • Formation of the first stars and galaxies in the early universe
  • Machine learning applications in modern astrophysics



Key publications: 


Link to all papers (via NASA ADS): NASA ADS

Link to all papers (via arXiv): arXiv


Evidence for mature bulges and an inside-out quenching phase 3 billion years after the Big Bang, Tacchella, S., et al., 2015, Science, 348, 314

The confinement of star-forming galaxies into a main sequence through episodes of gas compaction, depletion and replenishment, Tacchella, S., et al., 2016, Monthly Notices of the Royal Astronomical Society, 457, 2790

Evolution of density profiles in high-z galaxies: compaction and quenching inside-out, Tacchella, S., et al., 2016, Monthly Notices of the Royal Astronomical Society, 458, 242

A redshift-independent efficiency model: star formation and stellar masses in dark matter halos at z>4, Tacchella, S., et al., 2018, Monthly Notices of the Royal Astronomical Society, 868, 92

Dust attenuation, bulge Formation, and inside-out quenching of star formation in star-forming main sequence galaxies at z~2, Tacchella, S., et al., 2018, The Astrophysical Journal, 859, 56

Morphology and star formation in IllustrisTNG: the build-up of spheroids and discs, Tacchella, S., et al., 2019, Monthly Notices of the Royal Astronomical Society, 487, 5416

Stochastic modelling of star-formation histories II: star-formation variability from molecular clouds and gas inflow, Tacchella, S., et al., 2020, Monthly Notices of the Royal Astronomical Society, 497, 698

Fast, Slow, Early, Late: Quenching Massive Galaxies at z∼0.8, Tacchella, S., et al., 2022, The Astrophysical Journal, 926, 134

On the Stellar Populations of Galaxies at z=9-11: The Growth of Metals and Stellar Mass at Early Times, Tacchella, S., et al., 2022, The Astrophysical Journal, 927, 170

Hα emission in local galaxies: star formation, time variability and the diffuse ionized gas, Tacchella, S., et al., 2020, Monthly Notices of the Royal Astronomical Society