TITLE:   GCN CIRCULAR
NUMBER:  14845
SUBJECT: GRB 130610A: PAIRITEL NIR Afterglow Observations
DATE:    13/06/10 04:04:56 GMT
FROM:    Adam Morgan at U.C. Berkeley  <qmorgan@gmail.com>

A. N. Morgan & C. R. Klein (UC Berkeley) report:

We observed the field of GRB 130610A (Cummings et al., GCN 14842) with the
1.3m PAIRITEL located at Mt. Hopkins, Arizona. Observations began at
2013-Jun-07 03h35m37s UT, 0.39 hr after the Swift Trigger.  In  mosaics
(effective exposure time of ~5.85 minutes) taken simultaneously in the J,
H, and Ks filters, we detect the optical afterglow (Cummings et al., GCN
14842; Melandri et al., GCN 14843; Trotter et al. GCN 14844). The
preliminary K-band reduction is corrupted.

The preliminary photometry yields:

post burst
t_mid (hr) exp.(m)  filt  mag   m_err
0.47       5.85     J     17.49  0.16
0.47       5.85     H     16.95  0.20

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.