Romain Teyssier

About

Romain Teyssier is a Professor of Astrophysical Sciences and Applied and Computational Mathematics at Princeton University. His expertise includes cosmology, galaxy formation, and star formation. He is the main author of the RAMSES code, a massively parallel Adaptive Mesh Refinement code designed for self-gravitating, magnetized, radiative flows. His primary research involves performing simulations of cosmic structures using supercomputers to understand the origins of astrophysical objects such as stars and galaxies. Additionally, he models the evolution of the entire Universe within the context of Euclid and LSST. Teyssier has held positions at the University of Zurich and CEA Saclay, and has a background that includes a PhD in Astrophysics from Paris Saclay University and education at Ecole Polytechnique.

Research topics

• Physics
• Astrophysics
• Astronomy
• Theoretical physics

Selected publications

• Cosmic Dawn II (CoDa II): a new radiation-hydrodynamics simulation of the self-consistent coupling of galaxy formation and reionization

  Monthly Notices of the Royal Astronomical Society · 2020-05-06 · 173 citations

  articleOpen access

  ABSTRACT Cosmic Dawn II (CoDa II) is a new, fully coupled radiation-hydrodynamics simulation of cosmic reionization and galaxy formation and their mutual impact, to redshift z < 6. With 40963 particles and cells in a 94 Mpc box, it is large enough to model global reionization and its feedback on galaxy formation while resolving all haloes above 108 M⊙. Using the same hybrid CPU–GPU code RAMSES–CUDATON as CoDa I in Ocvirk et al. (2016), CoDa II modified and re-calibrated the subgrid star f…

  PublisherOA PDFDOI

• <i>Euclid</i> preparation: IX. EuclidEmulator2 – power spectrum emulation with massive neutrinos and self-consistent dark energy perturbations

  Monthly Notices of the Royal Astronomical Society · 2021-05-12 · 157 citations

  articleOpen access

  ABSTRACT We present a new, updated version of the EuclidEmulator (called EuclidEmulator2), a fast and accurate predictor for the nonlinear correction of the matter power spectrum. 2 per cent level accurate emulation is now supported in the eight-dimensional parameter space of w0waCDM+∑mν models between redshift z = 0 and z = 3 for spatial scales within the range $0.01 \, h\, {\rm Mpc}^{-1}\le k \le 10\, h\, {\rm Mpc}^{-1}$. In order to achieve this level of accuracy, we have had to improve the q…

  PublisherOA PDFDOI

• <i>Euclid</i>preparation

  Astronomy and Astrophysics · 2022 · 75 citations

  Euclid will be the first space mission to survey most of the extragalactic sky in the 0.95–2.02 µm range, to a 5 σ point-source median depth of 24.4 AB mag. This unique photometric dataset will find wide use beyond Euclid’s core science. In this paper, we present accurate computations of the Euclid Y E , J E , and H E passbands used by the Near-Infrared Spectrometer and Photometer (NISP), and the associated photometric system. We pay particular attention to passband variations in the field of vi…

  DOI

• Baryonification II: constraining feedback with X-ray and kinematic Sunyaev-Zel'dovich observations

  Journal of Cosmology and Astroparticle Physics · 2025-11-01 · 8 citations

  articleOpen accessCorresponding

  Abstract Baryonic feedback alters the matter distribution on small and intermediate scales, posing a challenge for precision cosmology. The new, component-wise baryonification (BFC) approach introduced in ref. 2507.07892 provides a self-consistent framework to model feedback effects for different observables. In this paper we use this framework to fit kinematic Sunyaev-Zel'dovich (kSZ) observations from the Atacama Cosmology Telescope (ACT) alongside halo X-ray gas fractions from eROSITA, invest…

  PublisherOA PDFDOI

• Dust-UV offsets in high-redshift galaxies in the Cosmic Dawn III simulation

  Astronomy and Astrophysics · 2025-10-07 · 2 citations

  articleOpen access

  Recent observations reveal puzzling spatial offsets between the ALMA dust continuum from bright galaxies at z = 5–7 and their UV emission seen by HST and JWST (e.g. ALPINE and REBELS surveys). We investigated this using Cosmic Dawn (‘CoDa’) III, a state-of-the-art radiation-hydrodynamics simulation of fully coupled galaxy formation and re-ionisation, which includes a dynamical dust model. Dust-UV offsets are predicted for massive, UV-bright galaxies, up to ∼2 pkpc for the most massive haloes ( M…

  PublisherDOI

Frequent coauthors

• F. Bournaud

  339 shared

• Jean‐Luc Starck

  CEA Cadarache

  235 shared

• A. Amara

  193 shared

• S. Farrens

  192 shared

• Alexandre Réfrégier

  183 shared

• S. Pires

  Université Paris Cité

  172 shared

• V. Pettorino

  Astrophysique, Instrumentation et Modélisation

  169 shared

• S. Pires

  CEA Paris-Saclay

  142 shared

Labs

• Department of Astrophysical Sciences, Princeton UniversityPI

Education

• PhD in Astronomy and Astrophysics, Physics

  Université Paris Cité Faculté de Santé

  1996

• Master in Science

  ENSTA ParisTech

  1994

• Bachelor

  École Polytechnique

  1992

Similar researchers at Princeton University

• Michael Straussh-149
• Bruce Draineh-93
• James Stoneh-86