[vsnet-grb-info 14572] iPTF14yb: RATIR Optical and NIR Observations of the optical transient

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  15886
SUBJECT: iPTF14yb: RATIR Optical and NIR Observations of the optical transient
DATE:    14/02/27 19:18:21 GMT
FROM:    Antonino Cucchiara at NASA/GSFC  <antonino.cucchiara at nasa.gov>

Antonino Cucchiara (ORAU/GSFC), 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), 
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 the transient iPTF14yb (Cenko et al., GCN 15883, Beardmore et al.,
GCN 15884) with the Reionization and Transients Infrared Camera (RATIR; www.ratir.org) 
on the1.5m Harold Johnson Telescope at the Observatorio Astronómico Nacional on
Sierra San Pedro Mártir from 2014/02 27.28 to 2014/02 27.54 UTC (20.53 to 26.68 hours 
after the reported time of discovery), 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.

For the source reported by Cenko et al. (GCN 15883), in comparison with the 
SDSS DR9 and 2MASS, we obtain the following detections and upper limit (3-sigma):

 r	22.28 +/- 0.09
 i	22.02 +/- 0.09
 Z	21.98 +/- 0.24
 Y	22.12 +/- 0.35
 J	21.88 +/- 0.35
 H	> 21.59

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

Our photometry indicates that the transient is fading in r band according to a
single power law with temporal index alpha=1.04. This behavior is also typical
of a long gamma-ray burst type transient as suggested by Cenko et al. (GCN 15883)

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