| Laboratoire : | Centre de Physique des Particules de Marseille Case 902 |
| 163 avenue de Luminy - 13288 Marseille Cedex 9 | |
| Directeur : | Cristinel Diaconu - 04.91.82.72.01 - diaconu@cppm.in2p3.fr |
| Correspondant : | William Gillard - 04.91.82.72.67 - gillard@cppm.in2p3.fr |
| Groupe d'accueil : | HESS-CTA |
| Chef de groupe : | Heide Costantini 04.91.82.72.57 - costantini@cppm.in2p3.fr |
| Responsable de stage : | Heide Costantini et Gabriel Emery - costant@cppm.in2p3.fr -emery@cppm.in2p3.fr |
Thématique : Astroparticules
The origin of galactic cosmic rays is one of the main open questions in high energy astrophysics. PeVatrons are objects capable of accelerating particles up to the PeV (=1015 eV) energies and are therefore considered the galactic cosmic ray accelerators. The principal signature of PeVatrons is ultrahigh-energy (exceeding 100 TeV) gamma radiation. The search for PeVatrons has recently been boosted by the discovery of several ultrahigh energy gamma-ray sources by the Large High Altitude Air Shower Observatory (LHAASO) [1].
Recently, the Supernova Remnant (SNR) G106.3-2.7 has been indicated as a highly promising PeVatron candidate [2]. In fact, G106.3-2.7 emits gamma-rays up to 500 TeV from an extended region ( 0.2o) well separated from the SNR pulsar (J2229+6114) and in spatial correlation with a local molecular cloud.
The CTA (Cherenkov Telescope Array) is a worldwide project to construct the next generation ground based very high energy gamma ray instrument. CTA will use tens of Imaging Air Cherenkov Telescopes (IACT) of three different sizes (mirror diameter of 4 m, 12 m and 23 m) deployed on two sites, one on each hemisphere (La Palma on the Canary Islands and Paranal in Chile). The observatory will detect gamma-rays with energy ranging from 20 GeV up to 300 TeV by imaging the Cherenkov light emitted from the charged particle shower produced by the interaction of the primary gamma ray in the upper atmosphere [3,4].
The CTA observatory completion is foreseen in 2025 but the first Large-Sized Telescope (LST1) is already installed and taking data in La Palma.
While the LST1 telescope cannot reach enough sensitivity to access energies above 100 TeV, it can provide precise angular resolution data for establishing the spectral morphology of this exciting PeVatron candidate in the 1-50 TeV energy region. Observations of G106.3-2.7 have started in 2022 and are presently on-going.
By using the Instrument Response Functions of the LST1 telescope, that have been recently determined within the CPPM group, the student will simulate the G106.3-2.7 source considering different morphological and spectral models based on recent phenomenological studies. The first goal will be to identify the capability of LST1 in determining the morphology of the source. Subsequently the simulated energy dependent sky maps will be compared to first observations with LST1 and this work will help to guide the data analysis and interpretation of these first early science data.
The student will use the official science tool of CTA (gammapy [5]) written in Python. The candidate should therefore have basic knowledge of Python programming.
This internship can eventually be continued with a PhD thesis.
References:
[1] Cao, Z., Aharonian, F.A., An, Q. et al. Ultrahigh-energy photons up to 1.4 petaelectronvolts from 12 ?-ray Galactic sources. Nature 594, 33–36 (2021).
[2] Z. Cao et al. Nature, 594, 33–36 (2021); M. Amenomori et al. Nature Astronomy, 5, 460–464 (2021)
[3] https://www.cta-observatory.org/
[4] Science with the Cherenkov Telescope Array: https://arxiv.org/abs/1709.07997
[5] https://docs.gammapy.org/1.1/