GRB 980326 Optical Observations

S. G. Djorgovski, S. R. Kulkarni, P. Cote, J. Blakeslee, J. S. Bloom, and S. C. Odewahn (Caltech), on behalf of the Caltech GRB collaboration:

The text of the GCN Circ. 57, submitted on 22 April 1998 PST:

We obtained R band images of the field of GRB 980326, using Keck-II 10-m telescope, on the night of 17 April 1998 UT. We clearly detect a galaxy coincident to within the astrometric errors (less than 0.3 arcsec) with the previously reported optical transient (cf. Groot et al. IAUC 6852 , and Kulkarni et al. GCN Circ. 33 ).

Using the magnitudes of stars 2 and 3 from Groot et al., we derive for this galaxy R = 25.5 +- 0.5 mag (preliminary reductions). This is about 0.6 magnitudes fainter than the tentative detection by Grossan et al. ( GCN Circ. 35 ), and is consistent with the upper limits reported by Valdes et al. ( GCN Circ. 56 ).

We interpret this object as the host galaxy of GRB 980326, probably with a negligible contamination from the OT itself. The difference in brightness from the measurements by Grossan et al. on 30 March 1998 UT suggests that some contribution from the OT was still present at that time, with the estimated OT magnitude of R ~ 25.8 at that epoch.

Further observations of this field are in progress.

This note can be cited.


CCD image in the R band obtained at the Keck-II telescope, obtained on UT 1998 April 17. The probable host galaxy of the GRB is circled. Its magnitude is R = 25.5 +- 0.5 mag (preliminary reductions). The field shown is approximately 108 arcsec square, with N up and E to the left.


This image is available in Postscript , and GIF formats.



A zoom-in on the previous image. The field shown is approximately 26.9 arcsec, N up, E to the left.


This image is available in Postscript , and GIF formats.





An earlier CCD image in the R band obtained at the Keck-II telescope, centered on the OT. The field shown is approximately 108 arcsec square, with N up and E to the left.



This image is available in Postscript , and GIF formats.



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