Development of multi-messenger analysis with the KM3NeT neutrino telescope. - Postdoc at Marseille, CPPM

The multi-messenger approach to astronomy makes use of the messenger particles of all four of nature’s fundamental forces to explore and understand the most violent phenomena in the universe (gamma-ray bursts, active galactic nuclei,fast radio bursts, supernova, etc.). A number of novel astronomical observatories, first imagined a generation ago, are now operational and providing access to cosmic probes such as neutrinos (IceCube/KM3NeT), gravitational waves (aLIGO/aVIRGO), charged particles (AUGER/TA) and photons (HESS, CTA, HAWC, Fermi, Swift, SVOM, etc.). The neutrinos of astrophysical interest need to be identified in the large background of atmospheric neutrinos and muons created by interactions of cosmic-ray particles in the atmosphere. Due to its full sky coverage and 100% duty cycle KM3NeT is ideally suited for the detection of transient astrophysical sources of neutrinos. Furthermore, the excellent angular resolution of KM3NeT is well matched to the narrow field of view of many of the photonic observatories. Rapid provision of alerts for interesting neutrino events will enable both ground and space based observatories to quickly point in the direction of the alert. This fast follow-up will be vital to catch any multi-messenger and multi-wavelengthcounterparts of these cataclysmic but short-lived phenomena.

With offline tools, the KM3NeT telescope is able to detect both muonic and electronic neutrino events with an unprecedented angular resolution of about 0.1° and 2° for track and cascade event topologies, respectively. The principal challenge will be to preserve this performance after adapting the offlinereconstruction software to a real-time framework that must be capable of handling the high trigger rate of events (about 1.5 kHz for the full detector) and providing a precise estimate of the neutrino direction withinin a few seconds. The expected event rate of KM3NeT is around about 200 neutrinos per day/site, while the partner observatories will typically follow only a few events per month. It is therefore important to only generatealerts for the most interesting neutrino candidates. A variety of different alert trigger strategies will be implemented: multiplet of events coming from the same direction in a short time window, single very high-energy events or single events from specific directions in the sky. The alert sending tool, implemented directly in the shore DAQ system, will channel the triggers to the external observatories.

Transient sources are generally detected by large field-of-view instruments such as Fermi, Swift, SVOM satellites. KM3NeT will receive these alert messages and will perform online search analysis to look for neutrino coincidenceswith GRBs, AGNs, FRBs... If a coincidence is found, a second alert message will be sent to the astrophysical community to request complement follow-up information.

The candidate will participate to the development of algorithms for fast real-time event reconstructions, to the implementation of the real-time system to distribute neutrino alerts to the worldwide astrophysical community andto perform the first analysis multi-messenger analysis.

As CPPM is the host laboratory of KM3NeT/ORCA, the candidate will also participate to the installation during sea campaigns, the calibration and the data analysis of the first lines.

The candidate should therefore have a good background in astroparticle physics and astrophysics and interest in the data analysis. The analysis will be performed using C++, python and ROOT languages. The evaluation of the applications (a single pdf file with cover letter, CV including publications, research statement, email addresses of three persons who can provide letters of recommendation) will start immediately, and will continue until the position is filled.