Speaker
Description
Pulsar wind nebulae (PWNe) are the dominant Ultra-high-energy (UHE) gamma-ray sources in the LHAASO catalog, suggesting that they are the dominant leptonic PeVatrons in our Galaxy. Despite this, very little is still known about their UHE gamma-ray emission, their number in the Galaxy, or their contribution to the gamma-ray emission of our Galaxy. In this work, we propose a self-consistent, data-driven model of the UHE gamma-ray emission of PWNe based on the ATNF and LHAASO catalogs. More specifically, we build a model of the UHE gamma-ray emission of PWNe that preserves the statistical relationships in the ATNF catalog and reproduces the number of PWNe detected in the LHAASO catalog.
To cope with the limited data available in the LHAASO catalog when performing fits to gamma-ray data, we introduce the concept of censored regression, which allows us to also use the information provided by unresolved sources. Using our model, we find that reproducing the number of PWNe detected by LHAASO requires either fractions of misaligned pulsars smaller (60\%) than usually found in the literature, or that some of the associations of PWNe with ATNF pulsars made by LHAASO may not be correct. In both cases, we find that, in order to reach self-consistency between radio and gamma-ray data, it is necessary that the majority of the unidentified sources in the LHAASO catalog are PWNe associated with an unseen pulsar.
Moreover, using our model, we also find that the contribution of unresolved PWNe to the total (diffuse) gamma-ray background measured by LHAASO in the $1-1000\,\rm{TeV}$ range is always smaller than 10\% (30\%). We conclude that PWNe mostly contribute to the source component of the UHE gamma-ray sky, while having almost no imprint on its diffuse component.
Based on: arXiv:2511.20452 [astro-ph.HE] (2025).
