PhD student in astroparticles (M/F)

Description of the thesis subject

COMCUBE-S is a swarm of nanosatellites dedicated to the study of gamma-ray bursts (GRBs). The mission was recently selected by the European Space Agency (ESA) for the launch of a constellation of 27 gamma-ray nanosatellites in the mid-2030s. An intermediate in-orbit demonstration mission with two nanosatellites is planned for 2030.
The objective of this thesis is to contribute to the development of COMCUBE-S for multi-wavelength astronomy. Our understanding of multiple transient sources detected by COMCUBE-S in gamma-rays will benefit from rapid follow-up at other wavelengths. This includes GRBs, active galactic nuclei (AGN), microquasars, soft gamma-ray repeaters, and cataclysmic variables. The large volume of alerts generated by COMCUBE-S, on the order of several per day, will be automatically processed by a broker infrastructure such as FINK before being sent to monitoring facilities and science teams.
The thesis project consists of three main parts: (i) improving source localization capabilities using artificial intelligence, (ii) simulating COMCUBE-S’s detection of transient sources based on their astrophysical properties, and (iii) developing science modules in FINK for automated management of constellation-generated alerts.
COMCUBE-S will implement novel aspects of inter-satellite links to produce rapid alert notifications with automatic source positioning. A first source localization will be obtained from the count rates of detectors across the constellation, which will be automatically transmitted to the ground in case of a triggering event. The method was originally developed for GRB localization by the CGRO-BATSE instrument, but its application to a large number of detectors distributed over several satellites constitutes a new approach. The doctoral student will develop a new localization method based on the use of an artificial neural network trained with simulated data. He will use a detailed numerical model of a nanosatellite to predict the count rates of all detectors as a function of the position, spectrum and flux of the source.
In a second part of the thesis, the doctoral student will study the detection with COMCUBE-S of various astrophysical transient sources (GRBs, AGN etc.). He will use several source catalogs to describe the emission spectrum and variability of the astrophysical objects studied. Using simulations of the COMCUBE-S response function,It will evaluate the detection rate of each type of source and the localization precision based on the work carried out in the first part of the thesis.
Finally, the PhD student will use the simulated COMCUBE-S detections to build new scientific modules in the FINK broker developed at IJCLab. The objective is to provide real-time transient classification, in order to automatically select the most promising alerts to be sent to the GCN network for follow-up observations at multiple wavelengths.
For his or her simulations, the PhD student will greatly benefit from the development and performance evaluation of the COMCUBE-S Compton gamma-ray telescope, which will be carried out at IJCLab during the thesis in collaboration with CEA-Irfu and University College Dublin. He or she will be able to actively participate in the laboratory instrumentation work and in the analysis of data collected during instrument testing. It will be very educational for the student to use these laboratory data for space mission performance simulations and an astrophysics application.

Work context

The Irène Joliot-Curie Physics of the Two Infinities Laboratory is a physics of the two infinities laboratory under the supervision of the CNRS, the University of Paris-Saclay and the University of Paris, born in 2020 from the merger of the five UMR located on the Orsay university campus: the Center for Nuclear and Material Sciences (CSNSM), the Laboratory of Imaging and Modeling in Neurobiology and Cancerology (IMNC), the Institute of Nuclear Physics of Orsay (IPNO), the Linear Accelerator Laboratory (LAL) and the Theoretical Physics Laboratory (LPT).

The laboratory’s research themes are nuclear physics, high energy physics, astroparticles and cosmology, theoretical physics, accelerators and particle detectors as well as technical research and development and associated applications for energy, health and the environment.

The structure has very significant technical capabilities (around 280 engineers and technicians) in all the major fields required to design, develop and implement the experimental devices necessary for its scientific activity: mechanics, electronics, computer science, instrumentation, acceleration techniques and biology techniques. These technical strengths represent a major asset for the design, development and use of the necessary instruments (accelerators and detectors). The presence of research infrastructures and technological platforms gathered on the laboratory site is also a major asset. Finally, around 90 ITAs from the administrative and support services work alongside the scientists and engineers.
The doctoral student will carry out their research work within the Astrophysics and Cosmochemistry (AC) team of the Astroparticles, Astrophysics and Cosmology (A2C) pole of the IJCLab laboratory. The team, which is based on a single site of the University of Paris-Saclay (in building 104 in the Orsay valley) includes seven permanent researchers and teacher-researchers, and one post-doctoral fellow.
As the position is located in a ZRR (restricted regime zone), recruitment is conditional upon obtaining a favorable opinion from the HFSD. Consequently, the start date is specified for information purposes only and may be postponed.

The position is located in a sector covered by the protection of scientific and technical potential (PPST), and therefore requires, in accordance with regulations, that your arrival be authorized by the competent authority of the MESR.