[vsnet-grb-info 19233] GRB 170317A: RATIR Optical and NIR Observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  20920
SUBJECT: GRB 170317A: RATIR Optical and NIR Observations 
DATE:    17/03/19 15:18:09 GMT
FROM:    Alan M. Watson at Instituto de Astronomia UNAM  <alan at astro.unam.mx>

Nat Butler (ASU), Alan M. Watson (UNAM), 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 170317A (LaPorte et al., GCN 20885) 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 2017/03 19.13 to 2017/03 19.30
UTC (41.26 to 45.37 hours after the BAT trigger), obtaining a total of
2.84 hours exposure in the r and i bands and 1.19 hours exposure in the
Z, Y, J, and H bands.

For a source within the enhanced Swift-XRT error circle (Beardmore et
al., GCN 20887), in comparison with the USNO-B1 and 2MASS catalogs, we
obtain the following detections and 3-sigma upper limits:

 r	23.70 +/- 0.10
 i	23.93 +/- 0.26
 Z	> 23.07
 Y	> 22.51
 J	> 22.27
 H	> 21.75

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

The source has faded by about a magnitude in r and i since our earlier
observations (Watson et al., GCN 20911).

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