TITLE:   GCN CIRCULAR
NUMBER:  21642
SUBJECT: GRB 170822A:BOOTES-5/JGT optical afterglow candidate
DATE:    17/08/22 11:12:19 GMT
FROM:    Juan Carlos Tello at IAA-CSIC  <jtello@iaa.es>

J. C. Tello, A. J. Castro-Tirado, R. Cunniffe, B.-B. Zhang, Y. Hu and A.
González-Rodríguez (IAA-CSIC), I. Carrasco (Univ. de Malaga), D. Hiriart,
W. H. Lee (UNAM), S. Jeong and I. H. Park (SKKU) and P. Kubanek (Inst. of
Physics, CZ) on behalf of a larger collaboration, report:

The 60 cm BOOTES-5/JGT at Observatorio Astronómico Nacional in San Pedro
Mártir (México) automatically responded in 7s (and 102s after the GRB onset) to
the Swift trigger of GRB 170822A (Melandri et al., GCN  21640).
The first unfiltered images (10 s exposures) were obtained at 09:13:38 UT
(mid exposure). At the position of the Swift  X-ray afterglow, we detect
the likely optical afterglow at a magnitude of 18.3 (comparing to
USNO-B1.0) and fading by 0.8 mag at 09:14:00 UT. The preliminary position
is RA (J2000) = 6:17:32.89, Dec (J2000) = +55:00:16.13 (+/- 0".5). Further
observations are being carried out. Spectroscopic observations are
encouraged.

We thank the staff at Observatorio Astronómico Nacional in San Pedro Mártir
for its excellent support.

[GCN OPS NOTE(22aug17):  Per author's request, in the second line
the "after the alert" was changed to "after the GRB onset".]