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GCN Circular 1925

Subject
GRB030226, BVRc observations
Date
2003-03-05T15:19:08Z (21 years ago)
From
Vladimir Sokolov at SAO RAS <sokolov@sao.ru>
T. Fatkhullin, V. Komarova, V. Sokolov, A. Cherepashchuk,
k. Postnov report for the larger GOSH collaboration:

The field of the GRB 030226 optical transient (Fox et al., GCN #1879)
was observed with CCD-photometer at the 1-m (Zeiss-1000) and 
SCORPIO at the 6-m telescopes of SAO RAS during three nights. 
Data from the 6-m telescope were obtained during time of the 
scheduled program "Search for optical emission of nearby pulsars" 
(P.I. V.G. Kurt). The weather conditions were slightly variable with 
cirruses and seeing of 2.5-3.0 arcsec in the first night, 2.5 arcsec 
seeing in the second one and 1.4 arcsec seeing in the third one. The B, 
V, Rc filters were used. Photometric calibration was performed using 
secondary standard stars of Henden et al., GCN #1916. The results of 
our photometry are presented below:

  Telescope |  Mean Date, UT | Tot. exp. | Filter | Mag.            
--------------------------------------------------------------
 Zeiss-1000 |    27.96 Feb.  |  2400s    |  V     | 22.07 +/- 0.19  
 Zeiss-1000 |    27.92 Feb.  |  2000s    |  Rc    | 21.75 +/- 0.18  

  6-m       |    28.99 Feb.  |  1200s    |  B     | 24.64 +/- 0.21  
  6-m       |    01.00 Mar.  |  1350s    |  V     | 23.66 +/- 0.16  
  6-m       |    28.99 Feb.  |  720s     |  Rc    | 22.96 +/- 0.12  

  6-m       |    01.94 Mar.  |  1200s    |  V     | 23.89 +/- 0.12
  6-m       |    01.92 Mar.  |  1200s    |  Rc    | 23.39 +/- 0.09

  
In the images obtained at the last night we clearly detect an 
extended object (R=22.9) 2.5 arsec South-East from optical 
transient (OT) position. Thus, the results of our aperture photometry 
of the OT may be affected by this object. We are planning to recalibrate 
the data provided additional realiable secondary standards are available.

We thank V.G. Kurt for sharing observational time and O. Spiridonova
for kind assistance in the Zeiss-1000 observations.

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