
arXiv: 1711.07482
The HAWC Collaboration has recently reported the detection of bright and spatially extended multi-TeV gamma-ray emission from Geminga, Monogem, and a handful of other nearby, middle-aged pulsars. The angular profile of the emission observed from these pulsars is surprising, in that it implies that cosmic-ray diffusion is significantly inhibited within ~25 pc of these objects, compared to the expectations of standard Galactic diffusion models. This raises the important question of whether the diffusion coefficient in the local interstellar medium is also low, or whether it is instead better fit by the mean Galactic value. Here, we utilize recent observations of the cosmic-ray electron spectrum (extending up to ~20 TeV) by the H.E.S.S. Collaboration to show that the local diffusion coefficient cannot be as low as it is in the regions surrounding Geminga and Monogem. Instead, we conclude that cosmic rays efficiently diffuse through the bulk of the local interstellar medium. Among other implications, this further supports the conclusion that pulsars significantly contribute to the observed positron excess.
11 pages, 3 figures, To Be Submitted to JCAP
High Energy Astrophysical Phenomena (astro-ph.HE), High Energy Physics - Phenomenology, High Energy Physics - Phenomenology (hep-ph), Astrophysics of Galaxies (astro-ph.GA), FOS: Physical sciences, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Astrophysics of Galaxies
High Energy Astrophysical Phenomena (astro-ph.HE), High Energy Physics - Phenomenology, High Energy Physics - Phenomenology (hep-ph), Astrophysics of Galaxies (astro-ph.GA), FOS: Physical sciences, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Astrophysics of Galaxies
| selected citations These citations are derived from selected sources. This is an alternative to the "Influence" indicator, which also reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically). | 29 | |
| popularity This indicator reflects the "current" impact/attention (the "hype") of an article in the research community at large, based on the underlying citation network. | Top 10% | |
| influence This indicator reflects the overall/total impact of an article in the research community at large, based on the underlying citation network (diachronically). | Top 10% | |
| impulse This indicator reflects the initial momentum of an article directly after its publication, based on the underlying citation network. | Top 10% |
