GCN Circular 3561

GRB 050408: ARC 3.5-meter NIR Observations

J. Flasher (Colorado), F. Hearty (Colorado), G. Stringfellow (Colorado), 
J. Walawender (Colorado), D. Q. Lamb (Chicago), T. Lisker (Washington), 
V. Debattista (Washington), J. Dembicky (APO), J. Barentine (APO), 
R. McMillan (APO), B. Ketzeback (APO), and D. G. York (Chicago) report 
on behalf of the ARC GRB team of the FUN GRB collaboration:

We observed the afterglow (Wells et al., GCN Circular No. 3191; Postigo
et al., GCN Circular No. 3192) of GRB 050408, a burst localized by
HETE-2 (Sakamoto et al., GCN Circular No. 3189), on the night of April
8th, using NIC-FPS on the ARC 3.5-meter telescope at Apache Point
Observatory.  The observation began at 04.47 UT (12.29 hours after the
burst) and ended at 07.06 UT (14.68 hours after the burst).  The
observation consisted of a series of 120-, 120-, 20-, and 20-second
exposures in Z, J, H, and Ks, respectively.   We have constructed
stacked images of the GRB field, corresponding to 20-minute exposures 
in each filter.  We detect the afterglow in all four filters, and 
measure Z = 21.8 � 0.12, calibrated relative to the SDSS stars in the 
field.

NIC-FPS is currently in its commissioning phase.

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