TITLE:   GCN CIRCULAR
NUMBER:  13987
SUBJECT: GRB 121123A: BOOTES-4 and IAC80 optical observations
DATE:    12/11/23 22:40:22 GMT
FROM:    Javier Gorosabel at IAA-CSIC  <jgu@iaa.es>

S. Guziy (Mykolaiv Nat. Univ.), R. Sanchez-Ramirez (IAA-CSIC), L.
Monteagudo Narvion (IAC), O. Lara, M. Jelinek (IAA-CSIC), P. Kubanek (IP
AS CR), Y. Fan, X. Zhao, J. Bai, C. Wang, Y. Xin (Yunnan National
Astronomical Observatory), Chenzhou Cui (Beijing National Astronomical
Observatory), R. Cunniffe, A.J. Castro-Tirado, J.C. Tello and J. Gorosabel
(IAA-CSIC), on behalf of a larger collaboration, report:

We have observed the GRB 121123A optical afterglow (GCN 13982, Helder et
al.) with the 0.6m BOOTES-4/MET robotic telescope at the Lijiang
Astronomical Observatory (China) and with the 0.82m IAC80 telescope
(Tenerife, Spain). The afterglow is detected as follows:

   Tel.  Date Nov  To-Tgrb Texp  Filter  Mag(Vega)
         UT-start   (hr)    (s)
 --------------------------------------------------------
  BOOTES-4 23.5196  2.43  5x120    r   18.87 +/- 0.15
  BOOTES-4 23.5711  3.66  5x120    r   19.01 +/- 0.15
  IAC80    23.7853  8.80  4x300    I   18.90 +/- 0.12

Our measurements confirm the shallow decay reported by Xu et al. (GCN 13986).