In the figure above, the arrows mark the optical transient which is likely to be the optical counterpart to the gamma-ray burst event GRB 971214, imaged on two consecutive nights with the SPIcam instrument on the ARC 3.5-m telescope at The Apache Point Observatory. We measure its position 11 56 26.35, +65 12 0.7 (J2000.0). The object was observed to fade by approximately 1.6 magnitudes in R-band over 24 hours. On Dec 15.5 UT, R=22.1+-0.1 and on Dec 16.6 UT, R=23.7+-0.3. The individual frames above are 1.50 arcminutes on an side. The structure seen in the sky background is due to scattered light defects from a nearby bright object.
Magnitudes were calibrated based on R_F magnitudes for bright stars in the field from the APM survey. In this system we measure coordinates for two reference stars. Ref1 (11 56 25.75, +65 11 36.0) R=20.10 +- 0.01, Ref2 (11 56 34.22, +65 11 44.2) R=20.78 +- 0.03.
Our R-band observations on Dec 15 and Dec 16 were approximately coincident with the reported MDM I-band detections by Halpern et al. (IAUC 6788), giving an R-I color for this object of (R - I) = 1.0 +/- 0.4. Within the quoted measuring errors, the color is constant during the fading.
Small frame blinking between the two images shown at the top of this page. The optical transient is seen to fade considerably in the second epoch. (Note: only WWW browsers which support animated GIFs properly display this figure.) Again, the fluctuating background is due to scattered light from a very bright, nearby star.
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