TITLE: GCN GRB OBSERVATION REPORT NUMBER: 692 SUBJECT: GRB000604, optical observations DATE: 00/06/07 17:09:24 GMT FROM: Alan H. Diercks at Caltech A. Diercks and I. Cotoros report on behalf of the Caltech-NRAO-CARA GRB collaboration: We have examined our Gunn-r images of the GRB000604 error box (Hurley et al, GCN #687) from June 6.24 - 6.28 UT (Cotoros et al, GCN #688) and do not detect the object reported by Leibowitz (GCN #690). The coordinates of Leibowitz's candidate fall within the overlap of our two pointings and the combined image (5x500s) has a 5-sigma detection limit measured relative to several USNO A2.0 stars of approximately r ~ 22.0 +/- 0.2, though this calibration should be considered preliminary pending more accurate photometry of the region. We find for Leibowitz's Star A (as shown in the finding chart http://wise-obs.tau.ac.il/~eran/GRB000604/) RA=15:35:52.6,10:41:08.8 +/- 1 arcsec measured against 58 USNO A2.0 stars. At the resolution of our images, Leibowitz's "Star B" is identifable as a galaxy. In addition, we have re-imaged the entire IPN error box with the Palomar 60" from June 7.26 - 7.30 UT in Gunn-r (5x500s). Lebowitz's object is not detected in our combined image which has a similar limiting magnitude as the June 6 data. Given the non-detection of Leibowitz's candidate in our data at epochs which bracket the Wise observations, we believe this object is not related to GRB000604. An image of the field is available at: http://astro.caltech.edu/~ad/grb000604/grb_im.ps This message may be cited.