GCN Circular 821

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. 


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