Point Source of Cosmic Rays in Orion

Abstract

By using Geiger-Müller counter telescopes with alt-azimuth mountings, a point source of cosmic rays was found. The telescopes were kept nearly horizontal so as to observe only high-energy cosmic rays which could pass through the thick layer of the atmosphere. Upon scanning the celestial sphere, a small part of it was observed again and again during the period from April, 1954 to December, 1956, and thus the existence of a point source was established. The declination of the point source was about 0.5°N and the right ascension was about 5 h 15 min. The average momentum of the primary particles effective for this observation would be about 280 Gev/c if they are protons. In this momentum range, the time average of the intensity was about 10% of the background cosmic rays, while there were some periodic variations during the period of observation.