Séminaires du
Département d'Astrophysique, Géophysique et Océanographie

Mercredi 28 août, 16h00

Salle de réunion AGO (local -1/14)
Institut d'Astrophysique et de Géophysique
Quartier Agora, Allée du 6 Août, 19C, B-4000 Liège 1 (Sart-Tilman)

The local positron flux: what do pulsars have to say about it?

Ruben Lopez-Coto
(INFN Padova)

Pulsars and their associated nebulae are the most commonly invoked astrophysical sources to explain the highest energy local cosmic ray positrons. However, a recent measurement of particle propagation around nearby pulsars by HAWC combined with the latest measurement of the local cosmic all-electron spectrum up to 20 TeV by HESS seemed to exclude this possibility. I will show in this presentation the latest experimental results on the Very-High-Energy gamma-ray emission surrounding Geminga and PSR B0656+14 by HAWC and discuss their implications. I will also show that the new observational facts can be reconciled with a pulsar origin, even in the case of a low diffusion close to the Earth, if an undiscovered nearby pulsar is the sole contributor to the local electron spectrum at the highest energies. Furthermore, I will give the predicted characteristics of this pulsar and show that the existence of such a pulsar with the required properties is not unlikely taking into account the properties of the pulsar population.