[vsnet-grb-info 25172] GRB 200228B: RATIR Optical Observations

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  27272
SUBJECT: GRB 200228B: RATIR Optical Observations
DATE:    20/02/29 15:51:14 GMT
FROM:    Rosa Leticia Becerra Godinez at Inst. de Astronoma,UNAM  <rbecerra at astro.unam.mx>

Rosa L. Becerra (UNAM), Alan M. Watson (UNAM), Nat Butler (ASU),
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 (U. Wash.), and
Vicki Toy (UMD) report:

We observed the field of GRB 200228B (Fermi GBM team, GCN 27253,
Laha, et. al. GCN 27254) 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 2020/02
29.36
to 2020/02 29.53 UTC (21.40 to 25.38 hours after the BAT trigger), obtaining
a total of 2.27 hours exposure in the r and i bands.

For a source within the Swift-XRT enhanced error circle (Evans et al., GCN
Circ. 27256),
in comparison with the SDSS DR9 and 2MASS catalogs, we obtain the following
upper
limits (3-sigma):

  r > 23.19
  i > 23.11

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.