[vsnet-grb-info 13071] GRB 130420A: PAIRITEL NIR detections

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  14408
SUBJECT: GRB 130420A: PAIRITEL NIR detections
DATE:    13/04/20 08:16:50 GMT
FROM:    Adam Morgan at U.C. Berkeley  <qmorgan at gmail.com>

A. N. Morgan (UC Berkeley) reports:

We observed the field of GRB 130420A (Page et al., GCN 14406) with the 1.3m
PAIRITEL located at Mt. Hopkins, Arizona. Observations began at 2013-Apr-20
07h37m23s UT, 8.9 minutes after the Swift Trigger.  In  mosaics (effective
exposure time of ~10 minutes) taken simultaneously in the J, H, and Ks
filters, we detect the optical afterglow (Guidorzi et al., GCN 14405; Page
et al., GCN 14406; Guver et al., GCN 14407).

The preliminary photometry yields:

post burst
t_mid (hr) exp.(m)  filt  mag   m_err
0.28       9.75     J     15.59  0.05
0.28       9.75     H     14.99  0.07
0.28       9.75     Ks    14.13  0.12

Observations are ongoing. All magnitudes are given in the Vega system,
calibrated to 2MASS. No correction for Galactic extinction has been made to
the above reported values.