TeV activity of Cygnus X-3 high mass binary system

Cygnus X-3 is a high mass X-ray binary and microquasar, with a compact object, which is either a neutron star or may be a black hole, and a companion object, which is a Wolf-Rayet star. The nature of the compact object is still uncertain. Cygnus X-3 galactic binary system has been regularly observed since a 1995 by SHALON Atmospheric Cherenkov telescope with the average gamma-ray flux (6.8 ± 0.7) × 10⁻¹³ cm⁻² s⁻¹. The observations of very high-energy gamma-radiation from the sources of this type would be important for understanding the nature of this astrophysical object.     

Sneutrinos from Cygnus X-3?

The possibility that the underground muons arriving from Cygnus X-3 are due to a flux of sneutrinos is analyzed. Crude approximations show that the muons can be due to a resonance production of light charged gauginos produced in sneutrino-electron collisions.     

Search for direct photons from S-Au collisions at 200 GeV/nucleon

The CERES experiment has measured inclusive photon production in S-Au collisions of 200 GeV/nucleon at the CERN SPS. No evidence for direct emission of photons was found. For the kinematic region 2.1<y<2.65 and 0.4 GeV/c<p⊥<2.0 GeV/c the yield andp⊥-dependence of the observed photons are well reproduced by hadron decays. Furthermore, their production rate is found to be proportional to the charged particle density. The systematic errors comparing the measured and expected photon yield result in an upper limit of 14% for the emission of direct photons in central S-Au collisions. For a photon source with a yield depending quadratically on the charged particle density the limit can be reduced to 7%.     

Search for direct photons from S-Au collisions at 200 GeV/nucleon

The CERES experiment has measured inclusive photon production in S-Au collisions of 200 GeV/nucleon at the CERN SPS. No evidence for direct emission of photons was found. For the kinematic region 2.1<y<2.65 and 0.4 GeV/c<p??<2.0 GeV/c the yield andp??-dependence of the observed photons are well reproduced by hadron decays. Furthermore, their production rate is found to be proportional to the charged particle density. The systematic errors comparing the measured and expected photon yield result in an upper limit of 14% for the emission of direct photons in central S-Au collisions. For a photon source with a yield depending quadratically on the charged particle density the limit can be reduced to 7%.     

Cygnus X-3: Six years of observations atE0≥50 TeV from the Plateau Rosa array

Summary Cygnus X-3 has been observed from 1982 to 1987 at primary energyE ₀≃10¹⁴ eV from the Plateau Rosa array. The absolute excess in the counting rate from the source region amounts to 0.15%, mostly concentrated in 1982 and 1986. The effect is observed in two classes of events although with small significance (2 and 1.4 s.d.). The 1986 data are consistent with observations of other arrays. The study of the 4.8 h time periodicity over a long observation time does not show any significant structure (2.5 s.d. excess at phase 0.2÷0.5). In 1982 and 1986 the light curves show respectively a wide excess between phases 0.60 and 0.85 and a 2.7 s.d. excess at phase 0.2÷0.25. The analysis of daily excesses from the source shows a good agreement with the expectations from pure statistical fluctuations, and no significant evidence of burst activity. To speed up publication, the proofs were not sent to the authors and were supervised by the Scientific Committee.     

A plausible explanation for muon events due to radiation from Cygnus X-3

The muon events produced at Soudan-I and NUSEX proton decay detectors due to radiation from Cygnus X-3 are given a plausible explanation on the basis ofE ₆ GUT. The possibility of verifying the explanation by using the accelerator experiments is suggested.