[vsnet-grb-info 16382] GRB 150402A: RATIR Optical Observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  17663
SUBJECT: GRB 150402A: RATIR Optical Observations
DATE:    15/04/03 19:03:37 GMT
FROM:    Owen Littlejohns at Az State U  <olittlej at asu.edu>

Owen Littlejohns (ASU), 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), 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 150402A (Cummings, et al., GCN 17661)
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
2015/04 3.02 to 2015/04 10.92 UTC (26.39 to 34.29 hours after the
BAT trigger), obtaining a total of 3.16 hours exposure in the r
and i bands.

Currently, there is only one source detected by the Swift/XRT
within the Swift/BAT error circle (Evans, GCN 17662).

  RA(J2000)  =  11h 34m 34.0s
  Dec(J2000) = +40d 58' 37.8"

This source has an error circle of 6.2 arcseconds. We detect
no uncatalogued transient inside the error circle for this source.
In comparison with the SDSS DR9, we obtain the following upper
limits (3-sigma):

  r     > 22.75
  i     > 22.68

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.