PhD subjects

6 sujets IRFU/DAP

Dernière mise à jour : 25-11-2020


««

• Astrophysics

 

Intergalactic magnetic field and gamma ray bursts with CTA

SL-DRF-21-0143

Research field : Astrophysics
Location :

Direction d’Astrophysique (DAP)

Laboratoire d’Etudes des Phénomènes Cosmiques de Haute Energie (LEPCHE)

Saclay

Contact :

Renaud Belmont

Thierry STOLARCZYK

Starting date : 01-09-2021

Contact :

Renaud Belmont
Université de Paris (Paris 7) - DRF/IRFU/DAP/LEPCHE


Thesis supervisor :

Thierry STOLARCZYK
CEA - DRF/IRFU/DAp/LEPCHE

+33 1 69 08 78 12

Personal web page : http://irfu.cea.fr/Pisp/thierry.stolarczyk/

Laboratory link : http://irfu.cea.fr/en/Phocea/Vie_des_labos/Ast/ast_technique.php?id_ast=3709

More : http://www.cta-observatory.org/

The intergalactic magnetic field pervading the cosmic voids is suspected to be a relic field originating from the very first epoch of the cosmic history. The goal of this PhD is to look for signatures of this field in the high-energy data of gamma-ray bursts, and to predict the ability of the future CTA observatory to constrain its properties. This work combines both theoretical modelling and analysis of simulated CTA data.
Dark Energy Tomography with the Euclid survey

SL-DRF-21-0206

Research field : Astrophysics
Location :

Direction d’Astrophysique (DAP)

Laboratoire CosmoStat (LCS)

Saclay

Contact :

Valeria Pettorino

Starting date : 01-10-2021

Contact :

Valeria Pettorino
CEA - DRF/IRFU/DAP/LCS


Thesis supervisor :

Valeria Pettorino
CEA - DRF/IRFU/DAP/LCS


Personal web page : https://www.valeriapettorino.com/

Laboratory link : http://www.cosmostat.org/

While the Universe is expanding with increasing velocity, the question of what is causing cosmic acceleration remains unsolved. Acceleration seems to act against gravitational attraction, as if a new source of energy, dubbed dark energy, were responsible for it.

This PhD proposal is meant to contribute to the Euclid mission, to tackle this dilemma by implementing the possibility to test dark energy at different redshifts, or what I refer to here as ‘dark energy tomography’, and integrate it in the Euclid Consortium validated likelihood.

The PhD student will be able to work at the interface between data and theory and concretely collaborate to a large collaboration like the Euclid satellite. Objectives include 1) extending the likelihood software to test dark energy at different redshift epochs, 2) contribute to the collaboration effort on comparing theoretical predictions with data 3) investigate different machine learning methods to reconstruct the dark energy contribution in each redshift bin.

Towards a 3D characterisation of supernova remants in X-rays

SL-DRF-21-0318

Research field : Astrophysics
Location :

Direction d’Astrophysique (DAP)

Laboratoire d’Etudes des Phénomènes Cosmiques de Haute Energie (LEPCHE)

Saclay

Contact :

Fabio Acero

Starting date : 01-10-2021

Contact :

Fabio Acero
CEA - DRF/IRFU/DAP/LEPCHE

0169084705

Thesis supervisor :

Fabio Acero
CEA - DRF/IRFU/DAP/LEPCHE

0169084705

More : http://github.com/facero/sujets2021

X-ray data are multidimensional by nature. For each photon the energy and position is recorded by the X-ray satellite. Here we propose to develop novel techniques to fully exploit the multidimensional nature of the data by combining blind source separation technique with feature learning.
Characterization of SVOM Gamma-Ray Bursts Afterglows using MXT data

SL-DRF-21-0153

Research field : Astrophysics
Location :

Direction d’Astrophysique (DAP)

Laboratoire des spectro-Imageurs spatiaux (LISIS)

Saclay

Contact :

Diego GOTZ

Starting date : 01-10-2021

Contact :

Diego GOTZ
CEA - DRF/IRFU/DAP/LISIS

+33-1-69-08-59-77

Thesis supervisor :

Diego GOTZ
CEA - DRF/IRFU/DAP/LISIS

+33-1-69-08-59-77

More : http://www.svom.fr

SVOM is a mission dedicated to the detection and characterization of Gamma-Ray Bursts (GRBs) and other multi-messenger sources, and it is scheduled for launch in June 2022.



SVOM carries a unique multi-wavelength payload, sensitive from gamma-rays to the visible band, which is complemented on ground by dedicated wide field and narrow field robotic telescopes, distributed over the entire Earth. The SVOM space segment consists of ECLAIRS, a coded mask telescope operating in the 4-150 keV energy range, GRM, a gamma-ray (20 keV-5 MeV) spectrometer, and two follow-up narrow field telescopes, VT (visible) and MXT (0.2-10 keV). The Microchannel X-ray Telescope (MXT) is a compact and light focusing X-ray telescope. The main goal of MXT is to precisely localize the X-ray counterparts of SVOM GRBs and to study in detail their spectral and temporal characteristics.



Gamma-Ray Bursts are issued either by the collapse of a very massive star (> 50 times the mass of the Sun) or by the coalescence of two compact objects (most likely neutron stars). In both scenari a short lived (less than ~100 s) gamma ray emission is followed by a longer lived (hours to days) X-ray emission, that can provide useful information about the GRB environment, the associated emission processes and, possibly, the nature of the GRB progenitors.



The successful PHD candidate will in first place contribute to the analysis the MXT flight model calibration data obtained in summer 2021 at the PANTER X-ray testing facility. In particular, the PHD student will be in charge of producing the MXT spectral response matrices before the SVOM launch, and of updating them during the first two years of the mission, by analyzing the in-flight calibration data.



The PHD student will be part of the MXT science team, act as a SVOM Burst Advocate, and thanks to this experience and to the deep instrumental knowledge acquired she/he will be able to correctly analyze, since the very beginning of the SVOM mission, X-ray afterglow data, and couple them to the multi wavelength data in order to build a clear phenomenological picture of the SVOM GRBs. In fact, the early GRB afterglow phase is still not fully understood, in particular from the point of view of the contribution of the GRB central engine to the so-called “plateau phases” of the afterglow light curve, whose interpretation could lead to a better understanding of the GRB progenitors.

Measuring the growth of massive structures in the distant Universe with deep spectroscopic surveys

SL-DRF-21-0166

Research field : Astrophysics
Location :

Direction d’Astrophysique (DAP)

Laboratoire de Cosmologie et d’Evolution des Galaxies (LCEG)

Saclay

Contact :

Emanuele DADDI

Starting date : 01-10-2021

Contact :

Emanuele DADDI
CEA - DRF/IRFU/DAP/LCEG


Thesis supervisor :

Emanuele DADDI
CEA - DRF/IRFU/DAP/LCEG


Cosmology - Clusters of galaxies - Artificial intelligence

SL-DRF-21-0332

Research field : Astrophysics
Location :

Direction d’Astrophysique (DAP)

Laboratoire de Cosmologie et d’Evolution des Galaxies (LCEG)

Saclay

Contact :

Marguerite PIERRE

Starting date : 01-10-2021

Contact :

Marguerite PIERRE
CEA - DRF/IRFU/SAp/LCEG

0169083492

Thesis supervisor :

Marguerite PIERRE
CEA - DRF/IRFU/SAp/LCEG

0169083492

Personal web page : https://sci.esa.int/s/WLg9apw

Laboratory link : http://irfu.cea.fr/dap/Phocea/Vie_des_labos/Ast/ast_groupe.php?id_groupe=972

More : Projet XXL : http://irfu.cea.fr/xxl

Clusters of galaxies are the most massive entities in the universe. As such, they constitute powerful cosmological probes.

The XLL survey is the largest programme of the European satellite XMM (X-ray band). It has enabled the detection of several hundreds of galaxy clusters.

The goal of the PhD is to perform the cosmological analysis of the complete XXL cluster sample by using innovative machine learning techniques.

 

Retour en haut