TITLE: GCN CIRCULAR NUMBER: 38427 SUBJECT: EP241201a: BOOTES-5 optical upper limit DATE: 24/12/03 10:36:32 GMT FROM: ipg@iaa.es I. Perez-Garcia, S.-Y. Wu, E. Fernandez-Garcia, M. D. Caballero-Garcia, G. Garcia-Segura, R. Sanchez-Ramirez, S. Guziy and A. J. Castro-Tirado (IAA-CSIC, Granada), C. Perez del Pulgar, A. Castellon (Univ. de Malaga), Y.-D. Hu (INAF-OAB, Brera), L. Hernandez-Garcia (Univ. de Valparaiso), M. Gritsevich (Univ. of Helsinki), D. R. Xiong (Yunnan Observatories of CAS), S. Jeong (ADD, Daejeon) and D. Hiriart and W. H. Lee (UNAM), on behalf of a larger collaboration, report: Following the detection of the fast X-ray transient EP241201a by the Einstein Probe (Chen et al. GCNC [38415](https://gcn.nasa.gov/circulars/38415)), the 0.6m BOOTES-5 robotic telescope at Observatorio Astronomico Nacional in San Pedro Martir (Mexico) observed the fast X-ray transient location starting on Dec 02, 05:32 UT (8.5 hours after trigger and 1 minute after notification) in different optical bands. No new optical source is detected on the co-added images (20*60 sec clear-filter) within the EP/WXT 3 arcmin radius error box down to 20.3 mag. Additionally, the source reported 4.8 hr later by Kinder (Lee et al, GCNC [38418](https://gcn.nasa.gov/circulars/38418)) is neither detected in our observation nor in the NOT one at a later epoch (Liu et al., GCNC [38425](https://gcn.nasa.gov/circulars/38425)). We thank the staff at Observatorio Astronomico Nacional in San Pedro Martir for their excellent support. View this GCN Circular online at https://gcn.nasa.gov/circulars/38427. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...