Late Central-engine Activity in GRB 180205A

Becerra, R. L.; Watson, A. M.; Fraija, N.; Butler, N. R.; Lee, W. H.; Troja, E.; Román-Zúñiga, C. G.; Kutyrev, A. S.; Álvarez Nuñez, L. C.; Ángeles, F.; Chapa, O.; Cuevas, S.; Farah, A. S.; Fuentes-Fernández, J.; Figueroa, L.; Langarica, R.; Quirós, F.; Ruíz-Díaz-Soto, J.; Tinoco, C. G. Tejada S. J.
The Astrophysical Journal, Volume 872, Issue 2, article id. 118, 11 pp. (2019).


We present optical photometry of the afterglow of the long GRB 180205A with the COATLI telescope from 217 s to about 5 days after the Swift/BAT trigger. We analyze this photometry in conjunction with the X-ray light curve from Swift/XRT. The late-time light curves and spectra are consistent with the standard forward-shock scenario. However, the early-time optical and X-ray light curves show atypical behavior; the optical light curve exhibits a flat plateau while the X-ray light curve shows a flare. We explore several scenarios and conclude that the most likely explanation for the early behavior is late activity of the central engine.