Identification of a likely radio counterpart to the rapid burster

We have identified a likely radio counterpart to the low-mass X-ray binary MXB 1730-335 (the Rapid Burster). The counterpart has shown 8.4 GHz radio o n/off behavior correlated with the X-ray on/off behavior as observed by the RXTE/ASM during six VLA observations. The probability of an unrelated, ran domly varying background source duplicating this behavior is 1%-3% dependin g on the correlation timescale. The location of the radio source is R.A. 17 (h)33(m)24.(s)61, decl. -33 degrees 23'19." 8 (J2000), +/-0." 1. We do not detect 8.4 GHz radio emission coincident with type II (accretion-driven) X- ray bursts. The ratio of radio to X-ray emission during such bursts is cons trained to be below the ratio observed during X-ray-persistent emission at the 2.9 sigma level. Synchrotron bubble models of the radio emission can pr ovide a reasonable fit to the full data set, collected over several outburs ts, assuming that the radio evolution is the same from outburst to outburst but given the physical constraints the emission is more likely to be due t o similar to 1 hr radio flares such as have been observed from the X-ray bi nary GRS 1915+105.