TITLE:   GCN CIRCULAR
NUMBER:  23749
SUBJECT: GRB 190114C: COATLI Optical Detection
DATE:    19/01/17 17:53:43 GMT
FROM:    Alan M. Watson at Instituto de Astronomia UNAM  <alan@astro.unam.mx>

Alan M. Watson (UNAM), Nat Butler (ASU), Rosa L. Becerra (UNAM), Diego
Gonz��lez (UNAM), William H. Lee (UNAM), Margarita Pereyra (UNAM), Carlos
Rom��n-Z����iga (UNAM), Alexander Kutyrev (GSFC), and Eleonora Troja
(GSFC) report:

We observed the field of GRB 190114C (Gropp et al., GCN Circ. 23688)
with the COATLI 50-cm telescope and interim imager at the Observatorio
Astron��mico Nacional on the Sierra de San Pedro M��rtir
(http://coatli.astroscu.unam.mx) from 2019-01-17 02:25 to 2019-01-17
07:56 (from 53.7 to 59.2 hours after the trigger), obtaining a total of
2.93 hours of exposure in the w filter.

We detect a source coincident with the enhanced XRT position (Osborne et
al., GCN Circ. 23704) and possible host galaxy (de Ugarte Postigo et
al., GCN Circ. 23692) with w = 20.32 +/- 0.07.

Our w magnitudes are calibrated against the USNO-B1 catalog (adjusted to
an approximate AB system) and are not corrected for Galactic extinction
in the direction of the GRB.

We thank the COATLI technical team (Fernando ��ngeles, Oscar Chapa,
Salvador Cuevas, Alejandro Farah, Jorge Fuentes, Rosal��a Langarica,
Fernando Quir��s, and Carlos Tejada) and the staff of the Observatorio
Astron��mico Nacional.