The Discovery of a 25-MIN Regular Modulation in the X-Ray Flux from 2S0142+61
Parmar, A. N.; White, N. E.; Giommi, P.; Mason, K. O.; Marshall, F. E.
Germany, United States, United Kingdom
Abstract
A 13 hr observation of 2S0142+61 on 1984 August 27 by EXOSAT shows the X-ray flux of 2S0142+61 to be modulated with a period of 1456+/-6 s. The 1 10 keV spectrum is two component with a ∼0.7 keV thermal and 0.0 energy index power law, with 30% of the total luminosity in the thermal component. The spectrum is absorbed by ∼1 × 1022 H cm-2. Only the hard component is pulsed with a 3 to 10 keV peak to mean amplitude of 35%. Below 2 keV the modulation is less than a few percent. The total 1 10 keV luminosity is 3.5 × 1032 erg s-1 for a distance of 100 pc. Possible optical counterparts are discussed.