[vsnet-grb-info 19301] GRB 170405A: RATIR Optical and NIR Observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  20996
SUBJECT: GRB 170405A: RATIR Optical and NIR Observations
DATE:    17/04/06 15:58:54 GMT
FROM:    Eleonora Troja at GSFC  <eleonora.troja at nasa.gov>

Eleonora Troja (GSFC), 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), 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 170405A (Troja, et al., GCN 20984) 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 2017/04 6.23 to 2017/04 6.48 UTC (10.93
to 16.85 hours after the BAT trigger), obtaining a total of 3.84 hours
exposure in the r and i bands and 1.62 hours exposure in the Z,
Y, J, and H bands.

For a source within the Swift-UVOT error circle (Troja, et al., GCN 20984),
in comparison with the USNO-B1 and 2MASS catalogs, we obtain the following
detections:

   r    22.67 +/- 0.05
   i    21.83 +/- 0.04
   Z    21.26 +/- 0.07
   Y    21.14 +/- 0.07
   J    20.75 +/- 0.07
   H    20.56 +/- 0.08


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

The nearby object noted by Malesani et al., (GCN 20988) is detected in all
our images and might affect our photometric measurements. The reported
values should be therefore considered as preliminary.

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

Further observations are planned.