Photometry of the Afterglow-like Transient iPTF14yb
ATel #5927; Peter Garnavich and Jason Wiggins (Notre Dame)
on 27 Feb 2014; 15:52 UT
Distributed as an Instant Email Notice Transients
Credential Certification: Peter Garnavich (pgarnavi@gmail.com)
Subjects: Optical, Gamma-Ray Burst, Transient
Referred to by ATel #: 5929
We observed the field of the GRB afterglow-like transient iPTF14yb (Cenko et al, GCN 15883; Cenko et al, ATEL 5924) with the KPNO-4m plus Mosaic-1.1 camera. Images were obtained in the Sloan-r filter beginning 12:55 UT on Feb 27 which is 26.6 hours after the first detection. A faint source at the position of the transient is seen in all four exposures. We estimate a r-band magnitude of 22.24+/-0.10 mag based on nearby stars in the SDSS catalog.
The late-time power-law decay slope is between 0.75 and 0.90 depending on the actual time of the burst. If the burst occurred near 9:54 UT on Feb 26 (20 minutes before the iPTF detection), then a single power-law with index of 0.79 fits the iPTF and KPNO-4m photometry.
