Abstract
A search for UHE (≥ 100 TeV) diffuse γ-ray emission from the Galactic disk has been carried out, through the excess in the cosmic-ray counting rate, by means of the EAS-TOP extensive air shower array at the Gran Sasso Laboratories. Measurements are performed from angular scales |b| ≈ 2° (as in 100 MeV satellite experiments, and as expected from CR interactions with the ISM) to |b| ≈ 10°. The obtained upper limits (90% c.l.) to the γ-ray excess over the cosmic-ray flux from the Galactic disk region are Iγ/Ip < 0.2% for |b| < 2°, Iγ/Ip < 0.04% for |b| < 5°, and Iγ/Ip < 0.02% for |b| < 12° at E0 > 130 TeV, corresponding to upper limits to the flux of Iγ < 3.2 × 10-13 cm-2 s-1 rad-1, Iγ < 2.8 × 10-13 cm-2 s-1 rad-1, and Iγ < 4 × 10-13 cm-2 s-1 rad-1.
Original language | English (US) |
---|---|
Pages (from-to) | 148-152 |
Number of pages | 5 |
Journal | Astrophysical Journal |
Volume | 397 |
Issue number | 1 |
DOIs | |
State | Published - 1992 |
Keywords
- Cosmic rays
- Gamma rays: Observations
ASJC Scopus subject areas
- Astronomy and Astrophysics
- Space and Planetary Science