Aims. We investigate the optical/near-infrared light curve of the afterglow of GRB 080710 in the context of rising afterglows. Methods. Optical and near-infrared photometry was performed using the seven-channel imager GROND and the Tautenburg Schmidt telescope. X-ray data were provided by the X-ray Telescope onboard the Swift satellite. We construct an empirical light curve model using the available broadband data, which is well-sampled in the time and frequency domains. Results. The optical/NIR light curve of the afterglow of GRB 080710 is dominated by an initial increase in brightness, which smoothly turns over into a shallow power law decay. At around 10 ks post-burst, there is an achromatic break from shallow to steeper decline in the afterglow light curve with a change in the power law index of Δα ∼ 0.9.Conclusions.The initially rising achromatic light curve of the afterglow of GRB 080710 can be accounted for with a model of a burst viewed off-axis or a single jet in its pre-deceleration phase and in an on-axis geometry. A unified picture of the afterglow light curve and prompt emission properties can be obtained with an off-axis geometry, suggesting that late and shallow rising optical light curves of GRB afterglows might be produced by geometric effects.
Kruhler, T. ....... A. Updike, et al. 2009. "The Bright optical/NIR Afterglow of the Faint GRB 080710 - Evidence of a Jet Viewed o-Axis." Astronomy & Astrophysics 508: 593.