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GCN Circular 396

Subject

GRB 990806, optical observations

Date

1999-08-08T12:32:55Z (26 years ago)

From

Jochen Greiner at Astrophys.Inst. Potsdam,Germany <jgreiner@aip.de>

J. Greiner (AI Potsdam, Germany), E. Pompei (ESO, Chile), S. Els (ESO, Chile),
D. Pinfield (Queens Univ. Belfast, Ireland), S. Brillant (ESO, Chile),
M. Sterzik (ESO, Chile), C. Wolf (MPIA Heidelberg), and A. Antonelli 
(Rome Obs., Italy) for the BeppoSAX team report: 

We have obtained BRI images of the GRB 990806 location (BeppoSAX mail n. 99/22
= GCN #392Loading...
 
 , BeppoSAX mail n. 99/23 = GCN #393Loading...
 
 ) with 
EFOSC at the 3.6 m  and the Wide-Field Imager at the  2.2 m telescopes
at La Silla/ESO  beginning at 14.5 hrs after the GRB event. The 
detailed observations were as follows:

  Telescope  Start time (UT)  Filter  Expo.Time
    2.2 m    07-08-1999  4:58    R       900 sec
    2.2 m    07-08-1999  5:15    R       900 sec
    3.6 m    07-08-1999  8:08    B      1500 sec
    2.2 m    07-08-1999  9:52    I      1200 sec
    2.2 m    07-08-1999 10:14    R       830 sec
    3.6 m    08-08-1999  7:36    B      1800 sec
    2.2 m    08-08-1999  8:45    R       900 sec
    2.2 m    08-08-1999  9:02    R       900 sec
    2.2 m    08-08-1999  9:18    R       900 sec
    2.2 m    08-08-1999  9:37    I       900 sec
    2.2 m    08-08-1999  9:53    I       900 sec

Comparison of the (summed R) images of the two nights do not show any
object with brightness variation more than 0.3 mag down to B = 25.2 mag, 
R = 23.5 mag and I = 18.0 mag. Photometric calibration was done against 
standard stars in the field SA 113, and the R band calibration is 
basically identical to that given in GCN #395Loading...
 
 .