[vsnet-grb-info 19052] GRB 170202A: RATIR Optical and NIR Observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  20595
SUBJECT: GRB 170202A: RATIR Optical and NIR Observations
DATE:    17/02/03 16:56:06 GMT
FROM:    Nat Butler at UC berkeley  <natxbutler at gmail.com>

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), Neil Gehrels (GSFC), Harvey
Moseley (GSFC), John Capone (UMD), V. Zach Golkhou (ASU), and Vicki Toy
(UMD) report:

We observed the field of GRB 170202A (Racusin, et al., GCN 20575) 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 2017/02 3.18 to 2017/02 3.57 UTC (9.92 to
19.17 hours after the BAT trigger), obtaining a total of 3.98 hours
exposure in the r and i bands and 1.68 hours exposure in the Z and Y bands.

For a source within the Swift-XRT error circle (Osborne, et al., GCN
20586), in comparison with the SDSS DR9 and 2MASS catalogs, we obtain the
following detections:

r = 20.68 +/- 0.01
i = 20.83 +/- 0.02
Z = 20.84 +/- 0.07
Y = 20.50 +/- 0.06

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

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