TITLE:   GCN GRB OBSERVATION REPORT
NUMBER:  821
SUBJECT: GRB000926 K'-band Observation 
DATE:    00/09/30 07:37:08 GMT
FROM:    Naoto Kobayashi at SUBARU, NAOJ  <naoto@naoj.org>

Naoto Kobayashi, Miwa Goto, Hiroshi Terada, Daigo Tomono
(Subaru Telescope, National Astronomical Observatory of Japan),
reported on behalf of SUBARU Telescope team and SUBARU IRCS team


On 29 Sept, 5:20-6:00 UT (29.24 UT), we have obtained 1800-sec K'
image of the field around the proposed optical transient (OT) of
GRB000926 (GCNC #803, Gorosabel et al.). We used the Subaru 8.2m
Telescope atop Mauna kea with a near-infrared camera and spectrograph
(IRCS) during its second engineering run. The candidate OT was clearly
detected in our image.

  http://www.SubaruTelescope.org/Latestnews/200010/GRB/grb000926.jpg

Seeing was about 0".7 in the K'-band. No associated host galaxy was
detected in our image. Since we did not have time to observe
standards, here we just show the relative magnitudes of the OT to a
number of field stars:


             relative       relative
             position      K'-magnitude
              to OT
     OT                    0.00 +- 0.04
   StarA     42"E         -0.45 +- 0.03
   StarB     30"E,34"S    -2.06 +- 0.01
   StarC     32"W         -0.80 +- 0.03

Assuming a probable V-K color of StarB (US170412+514636,
R=18.6,B=20.9), we have estimated rough K'-magnitude of the OT at
about K'=19 mag.


We have also uploaded the co-added fits image on the same web site
shown above.

  http://www.SubaruTelescope.org/Latestnews/200010/GRB/grb000926.fits

Please feel free to use it for detailed photometry if you have
any information on K'-magnitudes of the field stars. The original
pixel scale of our image is 0.058 arcsec/pix, but the posted image is
binned by 4-pix and the resultant pixel scale should be 0.233
arcsec/pix. North is to the top, East is to the left. 


This message is quotable in publications.