Last update on 11 March 2020
François Levrier
Maître de conférences de l'ENS Paris

  RESEARCH  -  TEACHING  -  OUTREACH -  EDUCATION
"Astronomy & Cosmology @ ENS"
Laboratoire de Physique de l'ENS
Département de Physique
École Normale Supérieure de Paris
24 rue Lhomond, 75231 Paris CEDEX 05, FRANCE



Office HL102A
Tel : +33 1 44 32 39 93
Fax : +33 1 44 32 39 92
e-mail : francois.levrier@ens.fr
NEWS

In a recently published paper led by Erwan Allys and in close collaboration with Stéphane Mallat, we introduce the reduced wavelet scattering transform (RWST), a statistical description with a small number of coefficients that characterizes complex structures arising from nonlinear phenomena, in particular interstellar magnetohydrodynamical (MHD) turbulence, independently of any specific priors. The RWST coefficients encode moments of order up to four, have reduced variances, and quantify the couplings between scales. To show the efficiency and generality of this description, we applied it successfully to three very different kinds of processes. With fewer than 100 coefficients when probing six scales and eight angles on 256 by 256 maps, the RWST allows to perform quantitative comparisons, infer relevant physical properties, and produce realistic synthetic fields. The paper is available here.

[older news]


  Essentials
 Research interests
Interstellar medium structure and dynamics
New techniques in radio-interferometry and astronomical data analysis
Databases and virtual observatory initiatives
[and many more...]
 Teaching activities
"Préparation à l'agrégation"
Interstellar medium course at M2 AAIS
Astrophysics TD at ENS Physics FIP
Order-of-magnitude physics TD at ENS Physics FIP
 Academic education
Graduate from ENS Paris (1996-2000)
"Agrégé" in Physics (2000)
Ph.D. in Astrophysics (2004)
HDR in Astrophysics (2016)
Looking for the S3-Tools?  They're here...
N.B. Major bug fix on 6 and 7 march 2012. Make sure you have the latest version !
INTERNSHIPS / PhDs  Available subjects - Get in touch !
Post-docs None at the moment
PhD Thesis None at the moment
M2 Level
 Data science meets Astrophysics in the Orion B Molecular Cloud [Description]

CURRENTLY
PhD Thesis
 Bruno Régaldo-Saint Blancard [2018-2021] : Towards realistic models of polarized CMB foregrounds
 Clément Walter [2019-2022] : On the path to primordial B-modes in CMB data

FORMER STUDENTS
PhD Thesis
Manuel Berthet [2013-2017]
M2 Level
 Bilal Ladjelate [2013] : Models of the physical and chemical structures of interstellar molecular clouds [Poster] [Report]
 Manuel Berthet [2012] : Filament and magnetic field orientation statistics in the diffuse ISM at large and small scales [Poster] [Report] [Defence]
 Rémi Paulin [2011] : Lifetimes of interstellar clouds [Poster] [Report]
M1 Level
 Antoine Maby [2017] : Polarization Measurement analysis [Description] [Slide] [Report]
 Brice Poillot [2011] : Development of extragalactic simulations for the Square Kilometer Array radio-interferometer [Slide] [Report]



?
Last night, Darth Vader came down from planet Vulcan and told me that if I didn't take Lorraine out that he'd melt my brain