[vsnet-grb-info 19394] GRB 170519A: RATIR Optical and NIR Observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  21109
SUBJECT: GRB 170519A: RATIR Optical and NIR Observations
DATE:    17/05/19 13:08:22 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), Harvey Moseley (GSFC), John
Capone (UMD), V. Zach Golkhou (ASU), and Vicki Toy (UMD) report:

We observed the field of GRB 170519A (Ukwatta, et al., GCN 21106) 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 2017/05 19.22 to 2017/05 19.32 UTC (1.8
minutes to 2.44 hours after the BAT trigger), obtaining a total of 1.41
hours exposure in the r and i bands and 0.60 hours exposure in the Z, Y, J,
and H bands.

The optical transient (GCN 21106; Izzo, et al., GCN 21108) is clearly
detected.  In comparison with the SDSS DR9 and 2MASS catalogs, we obtain:

  r 16.72 +/- 0.01
  i 16.50 +/- 0.01
  Z 16.34 +/- 0.01
  Y 16.25 +/- 0.01
  J 16.15 +/- 0.01
  H 15.87 +/- 0.01

These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the GRB.  The lightcurve rises in all bands
initially, peaking at i~16 at about 15 minutes after the GRB trigger, then
fading as t^(-0.8).

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