Search for gt 200 TeV photons from Cygnus X-3 in 1988 and 1989. [Cyg X-3]

• Published in: Physical review. D, Particles and fields Particles and fields, 1990-07, Vol.42:2
• Main Authors: Ciampa, D., Green, K., Kolodziejczak, J., Matthews, J., Nitz, D., Sinclair, D., Thornton, G., van der Velde, J.C., Cassiday, G.L., Cooper, R., Corbato, S.C., Dawson, B.R., Elbert, J.W., Fick, B.E., Kieda, D.B., Ko, S., Liebing, D.F., Loh, E.C., Salamon, M.H., Smith, J.D., Sokolsky, P., Thomas, S.B., Wheeler, B.
• Format: Article
• Language: English
• Subjects: BACKGROUND RADIATION; BINARY STARS; CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; COSMIC RADIATION; COSMIC RAY SOURCES; COSMIC SHOWERS; COSMIC X-RAY SOURCES; DISTRIBUTION FUNCTIONS; ELECTROMAGNETIC RADIATION; ELECTRONS; ELEMENTARY PARTICLES; ENERGY RANGE; ENERGY SPECTRA; FERMIONS; FUNCTIONS; GAMMA RADIATION; HADRONS; IONIZING RADIATIONS; LEPTONS; MASSLESS PARTICLES; MEASURING INSTRUMENTS; MUONS; PHOTONS; RADIATION DETECTORS; RADIATIONS; SCINTILLATION COUNTERS; SECONDARY COSMIC RADIATION; SHOWERS; SPECTRA; STARS; TEV RANGE 100-1000; TEV RANGE 640101 > Astrophysics & Cosmology-- Cosmic Radiation
• ISSN: 0556-2821; 1089-4918
• DOI: 10.1103/PhysRevD.42.281

Over a period of 16 months from April 1988 to August 1989, we have monitored the flux of cosmic-ray showers with energies above 2{times}10{sup 14} eV. We used a two-level array of scintillators covering an area of 3{times}10{sup 4} m{sup 2}. Counters on the surface measure the size and direction of each shower while counters buried 3 m beneath the surface sample the muons. By selecting showers with relatively few muons (less than one-tenth the average) the background of hadron-induced showers should be reduced by a factor of 150 or more while showers started by {gamma} rays should not be affected by this cut. We find no evidence for an excess from the direction of Cygnus X-3 either in ordinary showers or in muon-poor showers. For energies above 2{times}10{sup 14} eV, with 90% confidence, we find the excess flux of cosmic rays from the direction of Cygnus X-3 to be less than 1.3{times}10{sup {minus}13} cm{sup {minus}2}s{sup {minus}1} and the flux of photons (assuming they produce muon-poor showers) to be less than 1.5{times}10{sup {minus}14} cm{sup {minus}2}s{sup {minus}1}. This limit is substantially below the level of signals reported by earlier work. The period of observation included the intense radio bursts of June and July 1989. A portion of the data covering the 77-day period surrounding these events also showed no evidence for an excess.