[vsnet-grb-info 16595] GRB 150527A: RATIR Afterglow Detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  17876
SUBJECT: GRB 150527A: RATIR Afterglow Detection
DATE:    15/05/27 08:04:18 GMT
FROM:    Nat Butler at Az State U  <natbutler at asu.edu>

Nat Butler (ASU), Alan M. Watson (UNAM), Alexander Kutyrev (GSFC), William
H. Lee (UNAM), Michael G. Richer (UNAM), Chris Klein (UCB), Ori Fox (UCB),
J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara
(ORAU/GSFC), Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico
Ramirez-Ruiz (UCSC), José A. de Diego (UNAM), Leonid Georgiev (UNAM), Jesús
González (UNAM), Carlos Román-Zúñiga (UNAM), Neil Gehrels (GSFC), and
Harvey Moseley (GSFC) report:

We observed the field of GRB 150527A (Evans, et al., GCN 17874) 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 2015/05 27.29 to 2015/05 27.32 UTC (13.2 to
54.6 minutes after the BAT trigger), obtaining a total of 0.58 hours
exposure in the r, i, and z bands.

A source is detected within the Swift-XRT error circle.  In comparison with
the USNO-B1 catalog, we obtain the following detections and upper limit
(3-sigma):

  r     21.17 +/- 0.10
  i     20.83 +/- 0.14
  z     > 19.50

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

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