TITLE: GCN CIRCULAR NUMBER: 26754 SUBJECT: GRB 200114A: DDOTI/OAN optical observations report DATE: 20/01/15 03:17:26 GMT FROM: Emma Margarita Pereyra Talamantes at IA-UNAM Ensenada Margarita Pereyra (UNAM), Eleonora Troja (GSFC/UMD), Alan M. Watson (UNAM), Nat Butler (ASU), Rosa L. Becerra (UNAM), Diego Gonzalez (UNAM), Alexander Kutyrev (GSFC/UMD), William H. Lee (UNAM), and Tanner Wolfram (ASU), Simone Dichiara (GSFC/UMD) report: We observed the field of GRB 200114A detected by Fermi/GBM and AstroSat CZTI (Fermi GBM Team, GCN Circ. 26735; Gaikwad et al., GCN Circ. 26746), with the DDOTI/OAN wide-field imager at the Observatorio Astronómico Nacional on Sierra San Pedro Martir (http://ddoti.astroscu.unam.mx) from 2020-01-14 09:27 to 2020-01-14 13:18 UTC (5.78 to 9.63 hours after the event). We observed a region of 13.6 degrees in RA by 10.2 degrees in declination centered on the peak of the Fermi GBM on-ground localization at 13:17:31 -00:19:12 J2000 (Fermi GBM Team, GCN Circ. 26735). This region contains about 140 square degrees. We obtained about 30 to 36 minutes total exposure across the region. We calibrated our images against the APASS catalog. Our 10-sigma limiting magnitude are typically between w = 18.70 and w = 18.80. We found only one source with significant fading above our 10-sigma limit. This source is at 12:55:26.84 -00:21:23.8 J2000 and fades from w = 17.0 to w = 19.5 during our observations. However, the Pan-STARRS DR1 shows a 19 mag star at the source position, which rules it out as a GRB optical counterpart. Comparing to the USNO-B1 and Pan-STARRS DR1 catalogs, we detected no uncatalogued sources to our 10-sigma limit. We thank the staff of the Observatorio Astronómico Nacional in San Pedro Mártir. -- *Dr. Margarita Pereyra * *FFTF, Schlumberger Foundation Alumnae* ---------------------------------------------------------------------------------------------------------------- *Catedrático Conacyt* *Instituto de Astronomía de la UNAM,* *Km. 107 Carretera Tijua**na-Ensenada, * *Ensenada Baja California, México. C.P. 22860* Oficina: 405 Skype: margarita-pereyra