V1341 Cygni

G. Hasinger, A. Langmeier, and M. Sztajno, Max-Planck-Institut fur Extraterrestrische Physik, Garching; and N. White, EXOSAT Observatory, telex: "EXOSAT 1-to-10-keV observations of V1341 Cyg (= Cyg X-2 = 4U 2142+380) made between 1984 July 7.100 and 7.683 UT, with 7.8-ms time resolution, exhibit intensity-dependent quasiperiodic oscillations in the frequency range 30-50 Hz. The centroid frequency, f, of a broad (FWHM = 50 percent) bump in the power spectrum (16 sigma) shifts to higher frequencies when the source intensity, I, increases from 1 to 1.4 cts/s/cm**2 with (d log f)/dI = 1.7 +/- 0.3. The integrated excess power is on the order of 5 percent. We also find low-frequency noise (0-15 Hz), and its total power increases from 5.0 to 6.8 percent during intensity increases. The source spectra also show significant changes correlated with intensity. These phenomena are similar to the ones reported previously for GX 5-1 by van der Klis et al. (IAUC 4043) and for V818 Sco = Sco X-1 by Middleditch and Priedhorsky (IAUC 4060) and van der Klis et al. (IAUC 4068)."