Detection of ultrahigh-energy radiation from Scorpius X-1: Ooty observations during 1984-1987.

Abstract

A detailed study of showers arriving from the direction of Scorpius X-1 has shown strong evidence for emission of ultrahigh-energy radiation from Scorpius X-1 during the period 4 March--2 May 1986. 178 showers were observed in the source bin againat an expected background of 122.9. The chance probability for observing this excess has been estimated from simulations to be less than ${10}^{\mathrm{\ensuremath{-}}3}$. The flux observed during this period was (6.4\ifmmode\pm\else\textpm\fi{}1.6)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}12}$ ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}2}$ ${\mathrm{s}}^{\mathrm{\ensuremath{-}}1}$ at energies >2.5\ifmmode\times\else\texttimes\fi{}${10}^{14}$ eV, corresponding to a luminosity of 2\ifmmode\times\else\texttimes\fi{}${10}^{35}$ ergs ${\mathrm{s}}^{\mathrm{\ensuremath{-}}1}$.