RXTE observations of GX 3+1

Abstract

We report on new RXTE observations to search for millisecond X-ray variability from the bright Galactic bulge X-ray source GX 3+1. Although kilohertz quasiperiodic oscillations (QPO) have been detected now in 14 low mass X-ray binary (LMXB) systems they have, somewhat mysteriously, not yet been seen in the bright, persistent, Galactic bulge sources; GX 3+1, GX 9+1, GX 9+9 and GX 13+1. These systems have been typically classified as atoll sources and when bright are seen on the banana or upper banana branch in the X-ray color–color diagram. During our observations the source was also in a banana state and we did not detect kHz QPO. We place an upper limit on the amplitude of kHz QPO of about 1% rms.