Missions

Unveiling GRBs with LST-1 and the future LST2-4 telescope at very high energy.

The primary objectives of this postdoctoral research are closely aligned with the group's research topics:
Data analysis of events followed up by the LST, regardless of whether a detection is achieved, will constitute a major part of the work. A systematic analysis and the production of a catalog of observations (including both detections and upper limits) will be carried out during the postdoctoral contract. The addition of several LSTs to the array will add complexity to the analysis, and the postdoctoral researcher will contribute to the development of advanced analysis methods.
LAPP is also developing analysis techniques to better detect faint sources and optimize GRB follow-up. These techniques will be deployed and used over the coming months and years. The postdoctoral researcher will finalize the methods that take GRB variability into account and will integrate them into the LST analysis chain. This project will lead to both technical publications and scientific publications in the case of new detections.
Finally, the postdoctoral researcher will use GRB detections to work on the core research areas of the LAPP group. The two main topics are the extragalactic background light (EBL) and Lorentz invariance violation (LIV), for which the group's experts currently use data from active galactic nuclei. The novelty will be to use GRBs, which may represent very bright events detected at larger distances. This will provide a greater lever arm to constrain different EBL models or to better probe LIV.

Activités

The candidate will be a member of the Astro-gamma group at LAPP and, as such, will participate in the group's activities. They will also be a member of the CTA collaboration and will be strongly involved in activities related to the LSTs.
1. The first LST has been regularly acquiring data since 2020. The candidate will take part in the commissioning of the telescope and will play a leading role in the analysis of the first datasets and the initial follow-up of alerts.
2. The CTA group at LAPP is heavily involved in the development of data analysis tools. The candidate will be able to contribute to the development and optimization of these tools. LAPP is notably engaged in implementing innovative analyses based on Deep Learning, and the candidate can also participate in this development.
3. With the arrival of new LSTs during the course of the contract, the candidate will work on the analysis of stereo LST data, which will enable improved detection of GRBs.

Compétences

Due to the multiple and ambitious aspects of this project, the successful applicant should already count on a solid background in high-energy astroparticle physics. An experience in VHE gamma-ray astronomy will be a plus.

Teh candidate will need to show initiative and know how to manage students and international relations.

Contexte de travail

LAPP is a laboratory of the Institute of Nuclear Physics and Particle Physics (IN2P3), an institute of the National Center for Scientific Research (CNRS), which coordinates programs in these fields. LAPP is a joint research unit (UMR 5814) of the CNRS and the University of Savoie Mont-Blanc (USMB). More than 150 researchers, teacher-researchers, engineers, technicians, administrators, students and foreign visitors work there. The research carried out at LAPP aims to study the physics of elementary particles and their fundamental interactions, as well as to explore their links with the great structures of the Universe. The work of the LAPP teams aims, among other things, to understand the origin of the mass of particles, to unravel the mystery of dark matter or to determine what happened to the anti-matter present in our universe at the time of the Big Bang.

The Large Size Telescope (LST-1) at La Palma, one of the first telescopes to be operational within CTAO, will play a crucial role in GRB studies due to its large effective area and low energy threshold. The LST is of paramount importance for GRB studies due to several key factors.

The LST is designed to detect gamma rays in the energy range from 20 GeV to a few TeV, with an energy threshold lower than any other ground-based gamma-ray telescope. This low energy threshold is crucial for GRB studies, as it allows the LST to detect the high-energy tail of GRB emission. The LST-1 has a lightweight structure and advanced drive system, enabling it to slew rapidly to any position in the sky within 20 seconds. This fast response is essential for catching the prompt and early afterglow phases of GRBs, which can fade quickly.

The construction of 3 other LSTs has been started and the array will welcome a second telescope in 2025 for the first stereoscopic observation. The full array of 4 telescopes is planned to be finished in 2026.