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On December 27, 1997 at 08:23:06.72 UTC (00:23:06.72 PST) BATSE detected GRB 971227 (Trig. 6546). LOTIS received the Original GCN coordinates of RA=197.53°, Dec=65.80° at 08:23:10.9 UTC, approximately 4.2 seconds after the trigger. After slewing to the coordinates (~5.8 s) LOTIS began imaging the Original GRB position at 08:23:16.7 UTC, just 10.0 seconds after the BATSE trigger.

GRB 971227 Light Curve

The plot above illustrates the LOTIS response time to GRB 971227. The BATSE light curve ( > 20 keV) shows the burst with a duration of ~7 s. The grey area represents the integration time (10.0 s) of the first LOTIS image. LOTIS began imaging approximately 6.0 seconds after gamma-ray emission ceased and continued to image the area for the remaining five hours of darkness.

GRB 971227 Coverage Plot

The plot above illustrates the LOTIS coverage of the final BATSE error circle. The plot is centered near Final BATSE coordinates of RA=190.00°, Dec=54.31°, approximately 14° from the Original coordinates. The inner and outer ellipses represent the BATSE 1-sigma and 3-sigma error circles. The pseudo-rectangle represents the area covered by a single LOTIS camera (Camera #1) and each of the dots is a star detected by the system. The upper left hand corner of the rectangle is the center of the 2 x 2 array of cameras which is directed toward the Original BATSE coordinates (RA=197.53°,Dec=65.80°). The area covered by the remaining three LOTIS cameras is not plotted for clarity. The small red circle represents the position (RA=194.371°,Dec=59.272°) and 1-sigma error circle (10 arcmin radius) determined by the BeppoSAX WFC. The BeppoSAX coordinates of an afterglow detected by NFI at RA=194.313°,Dec=59.401° (1.5 arcmin radius error) 14 hours after the burst are within the BeppoSAX WFC error circle.

GRB 971227 Error Box

The LOTIS image above displays the area of the BeppoSAX afterglow of GRB 971227. This is the first LOTIS image (10.0-20.0 s after the start of the burst) from Camera #1. The yellow circle represents the 1.5 arcmin radius BeppoSAX error circle. No optical activity brighter than m ~ 12.0 was detected by LOTIS in this area or in the images taken in the six hours which followed.

To view the BeppoSAX error box in the first 56 LOTIS images (until ~20 minutes after the burst):
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For comparison with the LOTIS, image the image below shows a near infrared image (J band) of the BeppoSAX error box for GRB 971227 obtained with the Calar Alto 2.2-m telescope ( S. Klose and B. Stecklum, Thüringer Landessternwarte Tautenburg; Karl-Schwarzschild-Observatorium).

GRB971227 Error Box

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