PHD: Observations of protoplanets with the photonic lantern of FIRST-PL at the Subaru Telescope (M/F)

Job Description

Thesis Subject

Observations of protoplanets with the photonic lantern of FIRST-PL at the Subaru Telescope.
Compared to indirect detection methods, direct exoplanet detection remains one of the only ways to spectrally characterise the photons emitted or reflected by a planet, and thus learn more about the composition of its atmosphere. This goal is however demanding and requires the development of dedicated instrumental techniques, known as high-angular-resolution and high-contrast imaging techniques, in order to detect the faint light of a planet in the close environment of its host star.
It is in this context that the concept of the FIRST instrument (Fibered Imager foR a Single Telescope) was proposed. The original concept consists in transforming a telescope into an interferometer, in order to restore the angular resolution of the telescope down to the fundamental diffraction limit. Recently, the project developments have focused on the use of photonic components: an interferometric beam combiner on an integrated optics chip, and more recently a photonic lantern. The latter constitutes the heart of the FIRST-PL instrument, installed on the SCExAO platform at the Subaru Telescope. FIRST-PL has recently been validated and is open to the community for scientific observations.

PhD objectives:
The PhD will be carried out in Meudon, and will focus on exploiting the FIRST-PL instrument. A photonic lantern is a special type of optical fibre. On one side, a multimode fibre collects light at the telescope focal plane, then transitions into 19 single-mode fibres, whose output light is sent through a spectrograph to measure intensities as a function of wavelength. The intensity measured at each of these outputs corresponds to the decomposition of the incoming wavefront onto the 19 modes of the photonic lantern.
The data processing step consisting in recovering the observed object at the input of the photonic lantern from the 19 outputs, is at the heart of the ongoing developments. The PhD objectives can be described as follows:
- contributing to the existing data reduction pipeline
- understanding the limitations on measurement precision and fidelity (in particular noise sources and detector non-linearity), and defining calibration procedures
- processing on-sky data (acquired during engineering nights and as part of scientific observation programmes), and in particular developing and exploiting the Hα differential imaging mode for the detection of accreting protoplanets.
Additionally, depending on the skills and interests of the PhD candidate, the development of a laboratory test bench is envisaged, in order to explore the potential of the photonic lantern in the context of future instruments, in particular the future space mission HWO (Habitable World Observatory) or PCS (Planetary Camera and Spectrograph), a next-generation instrument for the ELT.
Further information on the FIRST project can be found on the laboratory website:
https://lira.obspm.fr/FIRST and on the SCExAO website: https://www.naoj.org/Projects/SCEXAO/scexaoWEB/030openuse.web/044firstpl.web/indexm.html
Proposed tasks for the recruited candidate will include:
• Contributing to the preparation of observing programs with FIRST-PL (accreting protoplanets, close binaries)
• Participating in observations (remotely or on-site in Hawaii if required)
• Analyzing the data : improving the data reduction pipeline, developing calibration procedures, and refining the observing strategy
• Publishing the resulting scientific outcomes

Skills:
• Data processing and signal processing
• Proficiency in Python
• Knowledge or interest for astrophysics
• Knowledge of optics and/or photonics (appreciated)
• Interest for experimental work
• English

Your Work Environment

The PhD will take place at LIRA (Laboratoire d'Instrumentation et de Recherche en Astrophysique), at the Meudon site of the Observatoire de Paris, within the HRAA (High Angular Resolution in Astrophysics) research group. The PhD will be co-supervised by E. Huby and S. Lacour, within the FIRST project team. The team also includes a PhD student and a postdoctoral researcher. Close collaborations are established with the SCExAO team at the Subaru Telescope, in particular S. Vievard and O. Guyon, providing an international working environment and collaboration opportunities. A meeting with the whole FIRST team takes place every week. The PhD will be based at the Meudon site, but on-site visits to Hawaii are also envisaged if necessary.

Geographically, the FIRST team is located in Meudon within a transverse group involving teams working on direct imaging (coronagraphy and interferometry) and atmospheric modelling of exoplanets. This facilitates close synergies with the pôleExoplanetary Systems, fostering direct interactions between instrumental development, observations, and scientific exploitation, particularly in the context of the detection and characterisation of young planetary systems. The working environment is strongly interdisciplinary, at the interface between astrophysics, optics, photonics, and signal processing.

Constraints and risks

None

Compensation and benefits

Compensation

2300 € gross monthly

Annual leave and RTT

44 jours

Remote Working practice and compensation

Pratique et indemnisation du TT

Transport

Prise en charge à 75% du coût et forfait mobilité durable jusqu’à 300€

About the offer

About the CNRS

The CNRS is a major player in fundamental research on a global scale. The CNRS is the only French organization active in all scientific fields. Its unique position as a multi-specialist allows it to bring together different disciplines to address the most important challenges of the contemporary world, in connection with the actors of change.

CNRS

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