Description du sujet de thèse

Title: Multi-messenger detection and analysis of high-energy neutrinos coinciding with fast radio bursts (FRBs) on the KM3NeT telescope

The neutrino team at the Subatech research laboratory in Nantes is proposing a research project in multi-messenger astronomy, focusing on the study of transient phenomena such as fast radio bursts (FRBs), potentially associated with the emission of high-energy neutrinos.
This research is based on neutrino telescopes such as KM3NeT, which consists of two detectors: ORCA (low energy) and ARCA (high energy).

Since 2022, another thesis in the group has been devoted to the search for neutrinos coinciding with FRBs, leading to methodological analyses and initial limits on detectable fluxes. Future work on statistical analysis of more than 900 FRBs is planned.

The new thesis project will continue this work by refining the analyses, differentiating the FRB sub-populations (repeaters or not, galactic or extragalactic) and the types of neutrino events.
The aim will be to adapt and improve the existing tools for a detector that has become more sensitive and for expanding catalogues of sources.

The expected results include :
- a better understanding of FRB radio and neutrino emission patterns
- updated analyses with more sources and data
- the development of tools to monitor the future growth of the detector
- the establishment of flux limits or, ideally, the first detection of a radio-neutrino association
- contributing to multi-messenger alerts and monitoring

Contexte de travail

Aims and Science Drivers - The multi-messenger astronomy of transient phenomena is currently a rapidly developing field in the disciplines linked to the study and understanding of the Universe. The simultaneous observation in 2017 of electromagnetic counterparts (visible, X, gamma) to the gravitational waves associated with the merger of two neutron stars and, a little more recently, the identification of high-energy neutrinos associated with electromagnetic signals (radio, X, gamma) coming from a known active galactic nucleus are the most demonstrative news. These observations combine all the messengers coming from the same astrophysical source, such as electromagnetic waves (radio, visible, up to the highest energies of X-rays), gravitational waves, but also in the form of particles (gamma rays, cosmic rays, neutrinos).

During these cataclysmic phenomena, which are among the most violent in the Universe, extraordinary amounts of energy are released over very short periods of time. The potential sources of these phenomena include gamma-ray bursts (GRBs), blazars (a class of galaxies with active nuclei - AGNs), magnetars (ultra-magnetised neutron stars) and fast radio bursts (FRBs). All these objects are considered to be possible cosmic accelerators and therefore sources of ultra-high-energy cosmic rays, which in turn generate very high-energy neutrinos. Contributing to such multi-messenger observations is one of the major objectives of existing neutrino telescopes such as IceCube, or those under construction such as KM3NeT. Multi-messenger observations are also the only way of identifying the sources of high-energy neutrinos (but this is also usually the case for understanding the origin of other messengers such as gravitational waves or gamma rays), and are therefore essential to this physics.

The mere observation of an astrophysical neutrino, however energetic, is of no use if its source is not identified, which absolutely requires the use of data, simultaneously or not, from other instruments.

The candidate should have :
- a Master 2 or equivalent in Physics
- A good level of English is required
- Good communication and writing skills in English - Ability to work both independently and collaboratively in an international team environment.

Contraintes et risques

- monitoring the state of the detector and the quality of the data for 1-2 weeks a year (online)
- follow the training courses required by the doctoral school (research ethics, open data, etc.).