Juan Diego Soler

Institute d'Astrophysique Spatiale

Universite Paris Sud
Centre Universitaire d'Orsay
Batiment 120-121
91405 ORSAY CEDEX, France

tel +33 1 69 85 86 20

jsolerpu [at] ias.u-psud.fr


I am a postdoctoral fellow at the MISTIC team in the Institut d'Astrophysique Spatiale (IAS). I study the polarization of the thermal emission by dust, which contains information about the magnetic field in the intestellar medium (ISM).

My work is right at the border between theory and observations. I use simulations of magnetohydrodynamic (MHD) turbulence in the ISM to characterize statistical tools to study polarization observations, particularly those by Planck-HIFI and BLASTpol.

My overarching interest is understanding the role of the magnetic field in the formation of structure in ISM, from molecular clouds to filaments and cores.

I did my PhD at the University of Toronto, where I worked in the Balloon-borne Astrophysics group I developed the thermal model and participated in the data reduction of BLASTpol. I also designed and assembled the carbon fibre gondola for Spider.

CV: in English, in Spanish




The magnetic field and the formation of structure in molecular clouds

ESA's Planck satellite has produced the first all-sky map of the polarized emission from dust at submm wavelengths. Compared with earlier ground-based and balloon-borne observations this survey is an immense step forward in sensitivity, coverage, and statistics.

Using the Planck observations within ten nearby (less than 450 pc from the Sun) molecular clouds, we evaluate statistically the relative orientation between the magnetic field projected on the plane of sky, inferred from the polarized thermal emission of Galactic dust observed by Planck at 353 GHz, and the gas column density structures, quantified by the gradient of the column density.

Within most clouds we find that the relative orientation changes progressively with increasing NH, from preferentially parallel or having no preferred orientation to preferentially perpendicular. In simulations of magnetohydrodynamic turbulence in molecular clouds this trend in relative orientation is a signature of Alfvenic or sub-Alfvenic turbulence, implying that the magnetic field is significant for the gas dynamics at the scales probed by Planck.

Planck intermediate results. XXXV. Probing the role of the magnetic field in the formation of structure in molecular clouds (corresponding author)

Magnetic field and column density measured by Planck towards the Taurus molecular cloud.



The Galactic magnetic field as revealed by Planck
Planck intermediate results. XXXIV. The magnetic field structure in the Rosette Nebula
Planck intermediate results. XXXIII. Signature of the magnetic field geometry of interstellar filaments in dust polarization maps
Planck intermediate results. XXXII. The relative orientation between the magnetic field and structures traced by interstellar dust
And more.



Analysis of synthetic observations from MHD simulations


We describe a morphological imprint of magnetization found when considering the relative orientation of the magnetic field direction with respect to the density structures in simulated turbulent molecular clouds. This imprint was found using the Histogram of Relative Orientations (HRO): a new technique that utilizes the gradient to characterize the directionality of density and column density structures on multiple scales. We present results of the HRO analysis in three models of molecular clouds in which the initial magnetic field strength is varied, but an identical initial turbulent velocity field is introduced, which subsequently decays.

An Imprint of Molecular Cloud Magnetization in the Morphology of the Dust Polarized Emission (2013ApJ...774..128S)




Ballooning Instrumentation

Spider

Spider is a balloon-borne polarimeter designed to observed the signature of the cosmic gravitational wave background in the CMB with unprecedented sensitivity and control of systematics.

In order to increase the portion of the payload mass devoted to the science equipment required to achieve this goals, we designed a carbon fibre gondola which guarantees the structural integrity of the experiment at 10 times the acceleration of gravity while using less that 10% of the total mass of the payload.

Design and construction of a carbon fiber gondola for the SPIDER balloon-borne telescope (2014SPIE.9145E..0TS)


BLASTPol

BLASTpol is a balloon-borne polarimeter designed to study the role played by magnetic fields in the star formation process. BLASTPol is the reconstructed BLAST telescope, with the addition of linear polarization capability. Using a 1.8m Cassegrain telescope, BLASTPol images the sky onto a focal plane that consists of 280 bolometric detectors in three arrays, observing simultaneously at 250, 350, and 500 micron. The diffraction-limited optical system provides a resolution of 30 arcseconds at 250 microns.

The thermal modelling of both BLASTpol and Spider is made using ThermalDesktop. The models are calibrated from the data obtained in previous flights and it allows to predict the temperature range of the components of the balloon-borne telescope.

Thermal design and performance of the balloon-borne large aperture submillimeter telescope for polarimetry BLASTPol (2014SPIE.9145E..34S)




Outreach




Link

BLAST
Balloon Astrophysics at UofT
Photography
The Cosmologists