[vsnet-grb-info 16374] GRB 150323C: possible host galaxy detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  17655
SUBJECT: GRB 150323C: possible host galaxy detection
DATE:    15/03/29 20:03:27 GMT
FROM:    Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst  <malesani at dark-cosmology.dk>

Daniele Malesani (DARK/NBI), Dong Xu (DARK/NBI), Pall Jakobsson (Univ. 
Iceland) and Jussi Harmanen (NOT and Univ. Helsinki) report on behalf of 
a larger collaboration:

We observed the field of GRB 150323C (Amaral-Rogers et al., GCN 17621; 
Stanbro, GCN 17627) using the Nordic Optical Telescope (NOT) located in 
La Palma. The mean time of the observation was March 28.21 UT, that is 
4.49 days after the GRB. A 20 min exposure was collected using the SDSS 
r filter.

Close to the position of the optical afterglow (Xu et al., GCN 17625; 
Watson et al., GCN 17632), we detect an object with r = 23.6 +- 0.2 AB 
(calibrated against nearby SDSS stars). This source is also marginally 
detected in the archival SDSS images with a comparable (though 
uncertain) brightness, and therefore an underlying galaxy must be 
contributing a significant fraction of the light.

We note a small, but significant offset between the afterglow and the 
galaxy positions. By registering astrometrically the afterglow image by 
Xu et al. (GCN 17625) with the new NOT data, we find an offset of 
approximately 0.65". Such an offset is not unprecedented, so that the 
SDSS/NOT object is still a viable host galaxy candidate for GRB 150323C.