TY  - JOUR
AU  - Rudolph, Annika
AU  - Bosnjak, Zeljka
AU  - Palladino, Andrea
AU  - Sadeh, Iftach
AU  - Winter, Walter
TI  - Multi-wavelength radiation models for low-luminosity GRBs, and the implications for UHECRs
JO  - Monthly notices of the Royal Astronomical Society
VL  - 511
IS  - 4
SN  - 0035-8711
CY  - Oxford
PB  - Oxford Univ. Press
M1  - PUBDB-2021-02589
M1  - arXiv:2107.04612
M1  - DESY-21-103
SP  - 5823 – 5842
PY  - 2022
AB  - We study the prompt phase of low-luminosity Gamma-Ray Bursts (LL-GRBs) as potential source of very-high-energy (VHE) gamma rays and ultra-high-energy cosmic rays (UHECRs).We model the spectral energy distribution of three representative examples (with observed properties similar to GRBs 980425, 100316D and 120714B)  self-consistently in a leptonic synchrotron self-Compton (SSC) scenario using the internal shock model for the relativistic outflow. To investigate the conditions under which inverse Compton radiation may lead to a peak in the GeV-TeV range potentially observable in Imaging Atmospheric Cherenkov Telescopes (IACTs), we vary the fraction of the energy budget supplying the magnetic field. As a second step, we determine the maximal energies achievable for UHECR nuclei. Assuming LL-GRBs to power the observed UHECR flux, we derive constraints on the baryonic loading and typical GRB duration by explicitly calculating the contribution of LL-GRBs to the diffuse extragalactic gamma-ray background. We find that LL-GRBs are potential targets for multi-mavelength studies and may be in reach of current/ future IACTs and optical/ UV instruments.For comparable sub-MeV emission and similar jet properties, the multi-wavelength predictions show a strong dependence on the magnetic field: weak (strong) magnetic fields induce high (low) fluxes in the VHE regime and low (high) fluxes in the optical. However, VHE emission might be suppressed by γγ-absorption close to the source (especially for high magnetic fields) or interactions with the extragalactic background light for redshifts z  >  0.1.For UHECRs, we find that the maximal energies of iron nuclei (protons) can be as high as  ≅ 10<sup>11</sup> GeV (10<sup>10</sup> GeV) if the magnetic energy density is large (where we predict a weak VHE component). These high energies are possible by decoupling the production regions of UHECR and gamma-rays in our multi-zone model. Finally, we find basic consistency with the energy budget needed to accommodate the UHECR origin from LL-GRBs.
KW  - cosmic radiation: UHE (INSPIRE)
KW  - cosmic radiation: spectrum (INSPIRE)
KW  - gamma ray: burst (INSPIRE)
KW  - energy: internal (INSPIRE)
KW  - iron: nucleus (INSPIRE)
KW  - gamma ray: background (INSPIRE)
KW  - energy: high (INSPIRE)
KW  - magnetic field: high (INSPIRE)
KW  - energy: density (INSPIRE)
KW  - energy: magnetic (INSPIRE)
KW  - VHE (INSPIRE)
KW  - acceleration (INSPIRE)
KW  - optical (INSPIRE)
KW  - shock waves (INSPIRE)
KW  - messenger (INSPIRE)
KW  - spectral (INSPIRE)
KW  - energy spectrum (INSPIRE)
KW  - synchrotron (INSPIRE)
KW  - decoupling (INSPIRE)
KW  - redshift (INSPIRE)
KW  - Cherenkov counter: atmosphere (INSPIRE)
KW  - imaging (INSPIRE)
KW  - suppression (INSPIRE)
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000766832600012
DO  - DOI:10.1093/mnras/stac433
UR  - https://bib-pubdb1.desy.de/record/459509
ER  -