[vsnet-grb-info 7433] GRB 090313 - PAIRITEL NIR detections

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  8995
SUBJECT: GRB 090313 - PAIRITEL NIR detections
DATE:    09/03/14 06:35:06 GMT
FROM:    Adam Morgan at PSU/Swift-UVOT  <qmorgan at gmail.com>

A. N. Morgan, J. S. Bloom, D. A. Perley (UC Berkeley),  and D. Starr
(UCB, LCOGT) report:

We observed the optical afterglow of GRB 090313 (Mao et al. 2009, GCN
8980) with PAIRITEL beginning at 2009-03-13 09:39 UT, 31 minutes after
the Swift Trigger.  We detect the afterglow (Chornock et al., GCN
8979) in all 111 47-second mosaics of 7.8 second simultaneous
exposures in the J, H, and Ks taken throughout the night.

Preliminary lightcurves indicate a shallowing of the temporal decay
rate during the 3.5 hours over which the afterglow was observed.  The
preliminary photometry yields:

post_burst
t_mid (hr) exp(s)  filt  mag   merr
0.941      1883    J     14.7  0.1
0.941      1883    H     13.8  0.1
0.941      1883    K     12.8  0.1

2.302      2331    J     15.6  0.1
2.302      2331    H     14.6  0.1
2.302      2331    K     13.8  0.1

3.512      1860    J     15.9  0.1
3.512      1860    H     15.4  0.1
3.512      1860    K     14.1  0.1

No correction for Galactic extinction has been made to the above
reported values.  Further observations are being taken tonight.