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GCN Circular 14514

Subject

GRB 130427A: Continued RATIR Optical and NIR Observations

Date

2013-04-30T14:42:55Z (11 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), Chris Klein (UCB), Ori Fox (UCB)
J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (UCSC),
Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz (UCSC),
Jos� A. de Diego (UNAM), Leonid Georgiev (UNAM), Jes�s Gonz�lez (UNAM),
Carlos Rom�n-Z��iga (UNAM), Neil Gehrels (GSFC), and Harvey Moseley (GSFC)
report:

We again observed the field of GRB 130427A (Maselli, et al., GCN 14448Not found
 
 
)
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 2013/04 30.14 to 2013/04 30.37 UTC
(67.58 to 73.15 hours after the BAT trigger), obtaining a total of 3.91
hours exposure in the r' and i' bands and 1.64 hours exposure in the Z, Y,
J, and H bands.

We continue to detect the optical/NIR afterglow (Elenin et al; GCN 14450Not found
 
 
)
in all bands.  In comparison with SDSS DR8 and 2MASS, we find:

  r'    19.39 +/- 0.01
  i'    19.31 +/- 0.01
  Z     18.89 +/- 0.03
  Y     18.75 +/- 0.03
  J     18.87 +/- 0.02
  H     18.56 +/- 0.03

These magnitudes are in the AB system and not corrected for Galactic
extinction in the direction of the GRB.  Uncertaints are 1-sigma.  The
source has faded by about 0.5 magnitude in all bands as compared to our
measurements on the previous night (Butler et al. 2013; GCN 14506Not found
 
 
).

We thank the staff of the Observatorio Astron�mico Nacional in San Pedro
M�rtir.