[vsnet-grb-info 19734] GRB 170822A: RATIR Optical and NIR Observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  21655
SUBJECT: GRB 170822A: RATIR Optical and NIR Observations
DATE:    17/08/23 13:59:54 GMT
FROM:    Alan M. Watson at Instituto de Astronomia UNAM  <alan at astro.unam.mx>

Alan M. Watson (UNAM), Nat Butler (ASU), Alexander Kutyrev (GSFC),
William H. Lee (UNAM), Michael G. Richer (UNAM), Ori Fox (STScI),
J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara
(UVI), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico
Ramirez-Ruiz (UCSC), Jesús González (UNAM), Carlos Román-Zúñiga (UNAM),
Harvey Moseley (GSFC), John Capone (UMD), V. Zach Golkhou (ASU), and
Vicki Toy (UMD) report:

We observed the field of GRB 170822A (Melandri et al., GCN Circ. 21640) with the
Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the
1.5m Harold Johnson Telescope at the Observatorio Astronómico Nacional on
Sierra San Pedro Mártir from 2017/08 23.44 to 2017/08 23.48 UTC (25.45
to 26.38 hours after the BAT trigger), obtaining a total of 0.69 hours
exposure in the r and i bands and 0.30 hours exposure in the Z,
Y, J, and H bands.

For a source within the Swift-XRT error circle, in comparison with the USNO-B1 
and 2MASS catalogs, we obtain the following upper limits (3-sigma):

 r	> 23.37
 i	> 22.87
 Z	> 21.99
 Y	> 21.56
 J	> 21.28
 H	> 20.82

These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the GRB.

The bright but rapidly-fading optical transient reported by Tello et al. 
(GCN Circ. 21642) is not seen in our images.

We thank the staff of the Observatorio Astronómico Nacional in San Pedro 
Mártir.