Back

GCN Circular 21915

Subject

GRB 170921A: RATIR Optical Afterglow Detection and NIR Observations

Event

GRB 170921A

Date

2017-09-22T23:22:09Z (8 years ago)

From

Nat Butler at Az State U <natbutler@asu.edu>

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), Jes��s
Gonz��lez (UNAM), Carlos Rom��n-Z����iga (UNAM), Harvey Moseley (GSFC), John
Capone (UMD), V. Zach Golkhou (ASU), and Vicki Toy (UMD) report:

We observed the field of GRB 170921A (D'Ai, et al., GCN 21901Loading...
 
 ) with the
Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the
1.5m Harold Johnson Telescope at the Observatorio Astron��mico Nacional on
Sierra San Pedro M��rtir from 2017/09 22.18 to 2017/09 22.51 UTC (13.82 to
21.76 hours after the BAT trigger), obtaining a total of 5.29 hours
exposure in the r and i bands and 2.22 hours exposure in the Z, Y, J, and H
bands.

For a source within the Swift-XRT error circle (Beardmore, et al., GCN
21906Loading...
 
 ), in comparison with the SDSS DR9 and 2MASS catalogs, we obtain the
following weak detections and upper limits (3-sigma):

  r = 24.45 +/- 0.34
  i = 24.38 +/- 0.34
  Z > 23.05
  Y > 22.83
  J > 22.47
  H > 22.19

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 Astron��mico Nacional in San Pedro
M��rtir.