Photometric Redshift of the GRB 981226 Host Galaxy

No optical afterglow was found for the dark burst GRB 981226 and hence noabsorption redshift has been obtained. We here use ground-based and spaceimaging observations to analyse the spectral energy distribution (SED) of thehost galaxy. By comparison with synthetic template spectra we determine thephotometric redshift of the GRB 981226 host to be z_phot = 1.11+/-0.06 (68%confidence level). While the age-metallicity degeneracy for the host SEDcomplicates the determination of accurate ages, metallicity, and extinction,the photometric redshift is robust. The inferred z_phot value is also robustcompared to a Bayesian redshift estimator which gives z_phot=0.94+/-0.13. Thecharacteristics for this host are similar to other GRB hosts previouslyexamined. Available low resolution spectra show no emission lines at theexpected wavelengths. The photometric redshift estimate indicates an isotropicenergy release consistent with the Amati relation for this GRB which had aspectrum characteristic of an X-ray flash.Comment: Accepted for publication in ApJ Letter