TITLE:   GCN CIRCULAR
NUMBER:  10472
SUBJECT: GRB 100305A: PAIRITEL NIR Upper Limits
DATE:    10/03/05 10:57:48 GMT
FROM:    Adam Morgan at U.C. Berkeley  <qmorgan@gmail.com>

A. N. Morgan, J. S. Bloom, and S. B. Cenko (UC Berkeley) report:

We observed the field of GRB 100305A (Troja et al., GCN 10470) with
the 1.3m PAIRITEL located at Mt. Hopkins, Arizona. Observations began
at 2010-03-05 09h29m30s UT, ~0.4 hours after the Swift trigger. �In
initial mosaics (effective exposure time of ~795.6 seconds) taken
simultaneously in the J, H, and Ks filters, we do not detect any
sources within the XRT error circle.

The preliminary photometry yields:

post_burst
t_mid(min) �exp(s) �filt � �U. Limit (3 sig)
34.6 � � � �795.6  �J � � � > 19.2
34.6 � � � �795.6  �H � � � > 18.0
34.6 � � � �795.6 � Ks � � �> 17.3

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