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We report on observations of the fading optical counterpart of the gamma-ray burst GRB 970228, made on 4~September~1997 using the STIS CCD on the Hubble Space Telescope. The unresolved counterpart is detected at V=28 +/- 0.25, consistent with a continued power-law decline with exponent -1.14 +/- 0.05. No proper motion is detected, in contradiction of an earlier claim. The counterpart is located within, but near the edge of, a faint extended source with diameter ~0."8 and integrated magnitude 25.7 +/- 0.25. Comparison with WFPC2 data taken one month after the initial burst and NTT data taken on March 13 shows no evidence for fading of the extended emission. After adjusting for the probable Galactic extinction in the direction of GRB 970228 of A_v=0.7, we find that the observed nebula is consistent with the sizes of galaxies of comparable magnitude found in the Hubble Deep Field and other deep HST images, and that only 2% of the sky is covered by galaxies of similar or greater surface brightness. We therefore conclude that the extended source observed about GRB 970228 is most likely a galaxy at moderate redshift, and is almost certainly the host of the gamma-ray burst., Comment: 7 pages (with 2 embedded figures), to be published in the Proceedings of the Fourth Huntsville Gamma-Ray Burst Symposium, held Sep 15-20, 1997, eds. C. A. Meegan, R. Preece, and T. Koshut

The Fallbrook Low-Frequency Immediate Response Telescope (FLIRT) is a phased radio array located in Fallbrook, CA which is remotely operated from Princeton, NJ. The experiment is designed to detect prompt radio counterparts of gamma-ray bursts (GRBs) at 74 MHz. Observations are triggered by the BATSE locations distributed through the GRB Coordinate Network and begin ∼10 s after BATSE detects a GRB. FLIRT is capable of detecting a 100 Jy source in a 10 s integration. A prompt radio burst at 74 MHz would follow a GRB by up to 30 minutes for bursts at cosmological distances. Thus, for cosmological GRBs, FLIRT can probe the pre-GRB radio emission. With even a crude second estimate of the GRB source distance, the dispersion measure can be used to estimate the column density of ionized hydrogen in the intergalactic medium.