GRB 050509B : Optical observations
 

Finding chart for GRB 050509B. Combined R:15x180s VLT+FORS2 image of the field, taken on 11.0 May, 2005 UT. The red circle indicates the revised (8") XRT error-circle (Rol et al. GCN #3395). The small arrows point to 6 objects detected within the error-circle.
The image size is about 50x35 arcsec. The seeing in the image is ~0.7".
 
 

  

NUMBER:  3410
SUBJECT: GRB050509B: Optical observations at the Very Large Telescope
DATE:    05/05/11 13:41:19 GMT

J. Hjorth, J. Sollerman, B. L. Jensen, J. P. U. Fynbo, P. Jakobsson,
J. M. Castro Cerón, K. Pedersen, H. Pedersen, D. Watson (Niels Bohr
Institute), R. Starling (Amsterdam), J. Gorosabel (IAA-CSIC Granada),
E. Ramirez-Ruiz (IAS, Princeton), C. Kouveliotou (NASA/MSFC) on behalf of GRACE, report :

"Using FORS2 on the 8.2m Antu Telescope at ESO/Paranal we have obtained 45 min R-band imaging (FWHM~0.7") of the XRT error circle for GRB 050509B (Swift trigger 118749, GCN 3381) at a mean epoch of May 11.0 UT. In the revised XRT error-circle (GCN 3395) we detect the four sources (S1-S4) mentioned in GCN 3401. None of these sources show pronounced variability with respect to the image posted in GCN 3401. The source previously designated S3 seems to be resolved into two sources separated by 1.8", or a new source is apparent in the centre of the error circle. The position of this source is:

S5:
RA(2000) = 12:36:13.8, Dec(2000) = +28:59:01.0

Another object is just included within the revised 90% XRT error-circle, the coordinates of this object is:

S6:
RA(2000) = 12:36.13.63, Dec(2000) = +28:59:07.7

An image of the field is shown at:

http://www.astro.ku.dk/~brian_j/grb/grb050509B/

We plan to monitor the field with the VLT in the following weeks. "

 

Last updated on May 11 2005, by Brian Lindgren Jensen