http://arxiv.org/abs/2303.13781
Ultra-high energy cosmic rays are the most extreme energetic particles detected on Earth, however, their acceleration sites are still mysterious. We explore the contribution of low-luminosity gamma-ray bursts to the ultra-high energy cosmic ray flux, since they form the bulk of the nearby population. We analyse a representative sample of these bursts detected by BeppoSAX, INTEGRAL and Swift between 1998-2016, and find they can produce a theoretical cosmic ray flux on Earth of at least $R_\text{UHECR} = 1.2 \times 10^{15}$ particles km$^{-2}$ century$^{-1}$ mol$^{-1}$. No suppression mechanisms can reconcile this value with the flux observed on Earth. Instead, we propose that the jet of low-luminosity gamma-ray bursts propels only the circumburst medium – which is accelerated to relativistic speeds – not the stellar matter. This has implications for the baryonic load of the jet: it should be negligible compared to the leptonic content.
E. Moore, B. Gendre, N. Orange, et. al.
Mon, 27 Mar 23
56/59
Comments: 5 pages, submitted to MNRAS