Turbulence in molecular clouds

New May-2019

Fully funded 3-year PhD project on Turbulence in Molecular Clouds 2019-2022
Title: Structures of turbulence dissipation in molecular clouds: From observations to numerical simulations.

This PhD project is part of a collaboration between observers and theoreticians of the interstellar medium in the frame of the project MIST (Molecules, magnetic fields and Intermittency in coSmic Turbulence) funded by the European Research Council. The aim of the PhD project is to characterize the structures that are involved in the dissipation of the turbulent kinetic energy in the interstellar medium.

The successful applicant will be deeply involved in, and will eventually lead, the observational part of the project which includes the data reduction and the analysis of molecular line observations of the CO molecule and its isotopologues carried out with NOEMA (existing data) and with ALMA (Cycle 7, if accepted). In parallel, he/she will develop the new tools needed to perform the comparison between spectral data cubes of the molecular gas emission and the 3D numerical simulations of turbulence dissipation performed in our team.

A more detailed description of the project is available here.

Pierre Hily-Blant
Edith Falgarone
Institut de Planétologie et d’Astrophysique de Grenoble Laboratoire de physique de l’École normale supérieure (LPENS)

The MIST project 2017-2022

Molecules, magnetic fields and Intermittency in coSmic Turbulence: Following the energy trail

ERC advanced grant MIST

P.I.: E. Falgarone



The discovery of molecules in the early universe is a challenging providence. Molecules unveil the truly cold universe in which stars form and their rich versatility provides unique diagnostics to unravel the "relative importance of purely gravitational effects and gas dynamical effects involving dissipation and radiative cooling", recognized 40 years ago by White and Rees to be a central issue in theories of galaxy formation. Molecules also reveal that cosmic turbulence is far less dissipative than predicted by cosmological simulations, with a broad equipartition in a vast variety of media between the thermal energy of the hottest phases and the turbulent energy of the coldest. Our project focuses on the physics of turbulent dissipation, and its link to the emergence of molecules, in the magnetized compressible medium where gravitational instability develops to form stars and seed galaxies in the early universe. It builds on a fundamental property of turbulence, its space-time intermittency: dissipation occurs in bursts. Our team will foster strong interactions between three main research axes: (1) observations of the chemical and thermal markers of turbulent dissipation in the high-redshift and local universe, (2) statistical analyses of the magnetic and velocity fields in samples of unprecedented size and sensitivity to study the non-Gaussian signatures of turbulent dissipation, and (3) numerical experiments dedicated to (a) the space-time structures of turbulent dissipation and the formation of molecules in their wake, and (b) the split of the energy trails between hot/thermal and cold/turbulent phases. This project will benefit from the prodigious capabilities of the ALMA and NOEMA interferometers, the launch of the JWST in 2018, and the Planck satellite data on polarized Galactic foregrounds. The ENS Physics Department, with its strong theoretical and experimental expertise on turbulence, is an ideal place to house such a project.

Case studies: The Polaris and the Taurus molecular clouds

  • Polaris Molecular Cloud
  • Taurus Molecular Cloud
  • Rapport de stage Julian Parissier
  • Rapport de stage Kirthika Mohan

    Polaris Molecular Cloud

    Taurus Molecular Cloud