TITLE: GCN CIRCULAR NUMBER: 38509 SUBJECT: GRB 241209A: BOOTES-7 and 2.2m CAHA early optical upper limits DATE: 24/12/10 00:49:36 GMT FROM: Youdong HU at INAF-OAB huyoudong072@hotmail.com
Y.-D. Hu (INAF-OAB), I. Perez-Garcia, A. J. Castro-Tirado, E. Fernandez-Garcia, S.-Y. Wu, M.D. Caballero-Garcia, R. Sanchez-Ramirez, S. Guziy, G. Garcia-Segura, I. Olivares, A. Sota (IAA-CSIC), C. Perez del Pulgar, A. Castellon, S. Castillo (Univ. de Malaga), L. Hernandez-Garcia (Univ. de Valparaiso), B.-B. Zhang (Nanjing Univ.) and A. Maury (Space, San Pedro de Atacama), on behalf of a larger collaboration, report:
Following the detection of the short-duration GRB 241209A by both Fermi/GBM (Fermi Team, GCN 38474) and Swift/BAT (Parsotan et al., GCN 38476), the 0.6m BOOTES-7 robotic telescope at San Pedro de Atacama (Chile) observed the GRB location starting on Dec 9, 05:39:06 UT (202 s after trigger) in different optical bands. No new optical source is detected on the co-added images (10x30s, clear-filter) at the position of the proposed near-IR counterpart candidate (Schneider et al. GCNC 38506; see also de Ugarte Postigo et al. CGCN 38484) down to 19.9 mag, consistent with other early-time reported limits (Kumar et al. GCNC 38481, Lipunov et al. GCNC 38483, Brivio et al., GCNC 38492, Pillas et al., GCNC 38500).
Additional observations were taken at the 2.2m CAHA telescope in Southern Spain (3x60s, starting on Dec 9, 06:03 UT, 28 min after trigger). Limiting magnitude for the resulting co-added image was 22.1 mag.
We thank the staff at Observatorio Astronomico de Calar Alto and San Pedro de Atacama celestial observations for their excellent support.
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