TITLE: GCN GRB OBSERVATION REPORT NUMBER: 536 SUBJECT: GRB000201 Optical Observations DATE: 00/02/09 03:34:54 GMT FROM: Robert Kehoe at U.Michigan/ROTSE R. Kehoe (Univ. of Michigan), J. Wren, R. Balsano (Los Alamos) and B. Lee (Fermilab) report on behalf of the ROTSE collaboration (U. Michigan/LANL/LLNL). We have observed the error box of GRB000201 provided by the Final and LocBurst Position Notices dated 1-Feb-00 using the ROTSE-I telephoto camera array. The initial BACODINE Notice localization fell below our elevation cut and was not observed. The ROTSE-I trigger protocol for Final Notices begins with 20 second exposures for the first few frames followed by 80 second exposures thereafter. All LocBurst response images are 80 second exposures. We have searched the LocBurst 1 sigma error region in the first half hour of observations and found no significantly varying objects. We have also searched all images at the location of the optical transient described in GCN #535 at RA = 139.03667, DEC = 18.10361 (J2000). For the nine LocBurst observations, this position falls in the overlap region between cameras 'a' and 'd', giving a degree of redundancy. The times and sensitivities (5 sigma cut-off) of these observations are: observation # time - T0 (s) limiting magnitude ------------- ------------- ------------------ 1-7 85.9 to 322 14.1 8-16 329 to 634 14.3 17-41 641 to 3055 15.1 38-41 co-add 2689 to 3055 15.8 No object is detected at the transient location in any image in any camera. To further explore the possibility of a dim counterpart, we have co-added the last four LocBurst images (see Table). No object is detected at the transient location in this image. Given our observation that any source at this location is around mag. 16 or dimmer within 5 minutes of the TAROT position, we believe this is not the optical counterpart to GRB000201. Further analysis to explore the wider field is in progress. This message may be cited.