Early detection of the optical counterpart to GRB 980329

Gorosabel, J.; Castro-Tirado, A. J.; Pedrosa, A.; Zapatero-Osorio, M. R.; Fernades, A. J. L.; Feroci, M.; Costa, E.; Frontera, F.; .

Early detection of the optical counterpart to GRB 980329

Authors

Gorosabel, J.

Castro-Tirado, A. J.

Pedrosa, A.

Zapatero-Osorio, M. R.

Description

We report optical observations of the GRB 980329 error box which represent the second earliest detection of the GRB 980329 optical transient. We determine R = 23.7 $\pm$ 0.5 mag on 29.89 March, which is consistent with R = 23.6 $\pm$ 0.2 mag as reported by Palazzi et al. (1998) on 29.99 March. Based on extrapolations of the light curve we claim that the R-band magnitude of the GRB 980329 host galaxy should lie in the range 26.8 mag $<$ R $<$ 29 mag. We also discuss the similarities with GRB 970111.
4 pages with three encapsulated PostScript figure included. Accepted for publication as a letter in Astronomy & Astrophysics