TeV halos and the role of pulsar wind nebulae as sources of cosmic ray positrons

Abstract

The recent detection of the Geminga PWN by HAWC in the multi-TeV band allows us to infer precious information about the transport of pairs in the immediate surroundings of the pulsar and on the spectrum of pairs contributed by a Geminga-like pulsar to the spectrum of pairs in the cosmic radiation. Moreover, this detection allows us to address the issue of how typical are the so-called TeV halos associated to PWNe. Our calculations confirm the need to have suppressed diffusion in a region of at least $20-50$pc around the pulsar, and are used here to infer precious constraints on the spectrum of pairs accelerated at the termination shock: more specifically, we discuss the conditions under which such a spectrum is consistent with that typically expected in a PWN and how it gets modified once it escapes the halo. Finally, we discuss the implications of the existence of a TeV halo around Geminga in terms of acceleration of protons in the pulsar environment, a topic of profound relevance for the whole field of particle acceleration and physics of pulsars.

15 pages, accepted for publication in PRD

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Cited by in corpus (9)

• Disclosing the catalog pulsars dominating the Galactic positron flux
• Constraining the slow-diffusion zone size and electron injection spectral index for the Geminga pulsar halo
• A 3D Diffusive and Advective Model of Electron Transport Applied to the Pulsar Wind Nebula HESS J1825-137
• Anisotropic Diffusion of $e^{\pm }$ in Pulsar Halos over Multiple Coherence of Magnetic Fields
• Extended TeV Halos May Commonly Exist around Middle-Aged Pulsars
• Regions of suppressed diffusion around supernova remnants?
• The environment of TeV halo progenitors
• PHECT: A lightweight computation tool for pulsar halo emission
• Mirage Sources and Large TeV Halo-Pulsar Offsets: Exploring the Parameter Space