TITLE: GCN CIRCULAR NUMBER: 8712 SUBJECT: GRB081222: Swift/UVOT further observations DATE: 08/12/23 12:15:56 GMT FROM: Alice Breeveld at MSSL-UCL Alice Breeveld (MSSL), Wayne Landsman (GSFC), Paul Kuin (MSSL) and Dirk Grupe (PSU) report on behalf of the Swift/UVOT team: Further analysis of Swift/UVOT data of GRB081222 (Grupe et al., GCN Circ. 8691), shows that the burst was detected in the v and b filters in addition to the white and u filters described in the initial circular (Breeveld et al., GCN Circ. 8696). The source is not detected in any of the UV filters, in single or co-added exposures. The initial magnitudes and upper limits are given in the table below: Filter Tstart(s) Tstop(s) Exp(s) Magnitude white 60 210 147 14.84+/-0.02 white 873 1023 147 17.36+/-0.03 v 602 622 20 16.20+/-0.02 b 528 548 20 16.86+/-0.02 u 272 522 246 16.32+/-0.03 uvw1 652 1815 142 >20.9 (3-sigma UL) uvm2 627 1790 127 >21.0 (3-sigma UL) uvw2 577 1914 124 >21.1 (3-sigma UL) A 49s UV grism spectrum was obtained beginning 216s after the trigger. The very low S/N quicklook spectrum shows a continuum of about 3e-15 erg/s/cm2/A longward of ~3400 A. No flux is detected shortward of 3400 A, even though the grism sensitivity increases toward shorter wavelengths. If this is the wavelength of the Lyman edge, then the redshift of GRB081222 is ~2.7. The detection of GRB081222 in the u filter and the non-detection in UVW1 filter are consistent with this redshift. The values quoted above are in the UVOT photometric system (Poole et al. 2008, MNRAS, 383, 627) and are not corrected for the expected Galactic extinction corresponding to a reddening of E(B-V)=0.021 mag in the direction of the burst (Schlegel et al. 1998).