1999A&AS..138..447V

We report on X-ray, optical and infrared follow-up observations of GRB 980703. We detect a previously unknown X-ray source in the GRB error box; assuming a power law decline we find for its decay index α←0.91 (3σ). We invoke host galaxy extinction to match the observed spectral slope with the slope expected from ``fireball'' models. We find no evidence for a spectral break in the infrared to X-ray spectral range on 1998 July 4.4, and determine a lower limit of the cooling break frequency: ν_c>1.3x10¹⁷ Hz. For this epoch we obtain an extinction of A_V=1.50 ±0.11. From the X-ray data we estimate the optical extinction to be A_V=20.2^+12.3_–7.3, inconsistent with the former value. Following Wijers & Galama (1999ApJ...523..177W), we determine intrinsic fireball properties for this burst.