Features of the gamma-ray pulsar halo HESS J 1831 -098
Abstract
Gamma-ray pulsar halos are ideal indicators of cosmic-ray propagation in localized regions of the Galaxy and electron injection from pulsar wind nebulae. HESS J 1831 -098 is a candidate pulsar halo observed by both the H.E.S.S. and HAWC experiments. We adopt the flux map of the H.E.S.S. Galactic plane survey and the spectrum measurements of H.E.S.S. and Fermi-LAT to study HESS J 1831 -098 . We find that HESS J 1831 -098 meets all the criteria for a pulsar halo. The diffusion coefficient inside the halo and the conversion efficiency from the pulsar spin-down energy to the electron energy are both similar to the Geminga halo, a canonical pulsar halo. The injection spectrum can be well described by an exponentially cutoff power law. However, the needed power-law term is very hard with p ≲1 if the diffusion coefficient is spatially and temporally independent. Considering the possible origins of the slow-diffusion environment, we adopt the two-zone diffusion model and the time-delayed slow-diffusion model. Both the models can interpret the H.E.S.S. and Fermi-LAT results with a milder p . A modified injection time profile may have a similar effect.
- Publication:
-
Physical Review D
- Pub Date:
- December 2022
- DOI:
- 10.1103/PhysRevD.106.123017
- arXiv:
- arXiv:2207.13533
- Bibcode:
- 2022PhRvD.106l3017F
- Keywords:
-
- Astrophysics - High Energy Astrophysical Phenomena
- E-Print:
- 15 pages (one column), 4 figures, 1 table