TITLE: GCN CIRCULAR NUMBER: 7224 SUBJECT: GRB 080121: Upper limit on X-ray afterglow DATE: 08/01/28 15:43:03 GMT FROM: Eleonora Troja at INAF-IASFPA E. Troja (INAF/IASFPA), and D. N. Burrows (PSU) report on behalf of the Swift XRT team: We have analysed 21 ks of XRT/PC data for the short GRB 080121 (trigger 301491; Cummings & Palmer, GCN 7209), starting 2.3 d after the burst. No X-ray afterglow candidate is found within the BAT error circle (GCN 7209). A faint source is detected within the BAT error circle at RA(2000) = 09h 08m 46.36s, Dec(J2000) = +41d 51' 21.1'' with an error radius 5 arcsec (90% containment). This source has a count rate of ~2E-03 cts/s, and displays no fading behaviour. We place a 3 sigma upper limit of 1E-03 cts/s on the X-ray afterglow count rate, which corresponds to an unabsorbed flux of 3.7E-14 erg/cm^2/s (over 0.3-10 keV), assuming a Crab-like spectrum and a Galactic absorption of 1.23E+20 cm^-2 (Kalberla et al. 2005). This circular is an official product of the Swift XRT Team.