Time variability of TeV cosmic ray sky map
- The variation in the intensity of cosmic rays at small angular scales is attributed to the interstellar turbulence in the vicinity of the Solar system. We show that a turbulent origin of the small-scale structures implies that the morphology of the observed cosmic ray intensity skymap varies with our location in the interstellar turbulence. The gyroradius of cosmic rays is shown to be the length scale associated with an observable change in the skymap over a radian angular scale. The extent to which the intensity at a certain angular scale varies is proportional to the change in our location with a maximum change of about the amplitude of intensity variation at that scale in the existing skymap. We suggest that for TeV cosmic rays a measurable variation could occur over a time-scale of a decade due to the Earth’s motion through the interstellar medium, if interstellar turbulence persists down to the gyroradius, about 300 μpc for TeV-ish cosmic rays. Observational evidence of the variability, or an absence of it, could provide a usefulThe variation in the intensity of cosmic rays at small angular scales is attributed to the interstellar turbulence in the vicinity of the Solar system. We show that a turbulent origin of the small-scale structures implies that the morphology of the observed cosmic ray intensity skymap varies with our location in the interstellar turbulence. The gyroradius of cosmic rays is shown to be the length scale associated with an observable change in the skymap over a radian angular scale. The extent to which the intensity at a certain angular scale varies is proportional to the change in our location with a maximum change of about the amplitude of intensity variation at that scale in the existing skymap. We suggest that for TeV cosmic rays a measurable variation could occur over a time-scale of a decade due to the Earth’s motion through the interstellar medium, if interstellar turbulence persists down to the gyroradius, about 300 μpc for TeV-ish cosmic rays. Observational evidence of the variability, or an absence of it, could provide a useful insight into the physical origin of the small-scale anisotropy.…
| Author details: | Rahul Kumar, Noemie Globus, David Eichler, Martin PohlORCiDGND |
|---|---|
| DOI: | https://doi.org/10.1093/mnras/sty3141 |
| ISSN: | 0035-8711 |
| ISSN: | 1365-2966 |
| Title of parent work (English): | Monthly notices of the Royal Astronomical Society |
| Publisher: | Oxford Univ. Press |
| Place of publishing: | Oxford |
| Publication type: | Article |
| Language: | English |
| Date of first publication: | 2018/11/21 |
| Publication year: | 2018 |
| Release date: | 2021/04/12 |
| Tag: | cosmic rays |
| Volume: | 483 |
| Issue: | 1 |
| Number of pages: | 5 |
| First page: | 896 |
| Last Page: | 900 |
| Funding institution: | Israel-U.S. Binational Science FoundationUS-Israel Binational Science Foundation; Israel Science Foundation (ISF)Israel Science Foundation; ISF-University Grant Commission (India); Joan and Robert Arnow Chair of Theoretical Astrophysics; Max-Planck/Princeton Center for Plasma Physics; NSFNational Science Foundation (NSF) [AST-1517638]; Koret Foundation |
| Organizational units: | Mathematisch-Naturwissenschaftliche Fakultät / Institut für Physik und Astronomie |
| DDC classification: | 5 Naturwissenschaften und Mathematik / 52 Astronomie / 520 Astronomie und zugeordnete Wissenschaften |
| Peer review: | Referiert |
| Publishing method: | Open Access / Green Open-Access |
