TITLE: GCN GRB OBSERVATION REPORT NUMBER: 2824 SUBJECT: HST Observations: XRF 040701 and 040812 DATE: 04/10/19 16:07:38 GMT FROM: Shri Kulkarni at Caltech S. Kulkarni, A. Soderberg and D. Fox report on behalf of the Caltech/Carnegie/NRAO collaboration: "As part of our large HST program on GRBs and XRFs, we have used ACS to observe the fields of XRF 040701 and XRF 040812. Observations were taken in the F625W (r) and F775W (i) filters 39 and 60 days after the burst (XRF040701) and 32 and 54 days after the burst (XRF040812). Comparison of the two epochs for each XRF does not reveal a variable source within the 1-arcsec position of the putative Chandra X-ray afterglow candidates (GCNs 2630 and 2655 for XRFs 040701 and 040812, respectively). Our 3-sigma limits are the following: XRF Filter Limit: ============================================== 040701 F625W 27.5 F775W 27.0 040812 F625W 27.5 F775W 27.0