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.
Gonz��lez-Rodr��guez (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 Astron��mico Nacional in San Pedro
M��rtir (M��xico) 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 Astron��mico Nacional in San Pedro M��rtir
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".]