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| Paper: |
Optical and NIR Monitoring of the GRB020405 Afterglow |
| Volume: |
312, Third Rome Workshop on Gamma-Ray Bursts in the Afterglow Era |
| Page: |
225 |
| Authors: |
Masetti, N.; Palazzi, E.; Pian, E.; Simoncelli, A.; Hunt, L.K.; Maiorano, E.; Savaglio, S.; Rol, E.; Levan, A.; Castro-Tirado, A.J.; Fruchter, A.; Greiner, J.; Hjorth, J.; Wijers, R.; van den Heuvel, E.P.J.; GRACE collaboration, on behalf of the |
| Abstract: |
Optical and near-infrared (NIR) observations of GRB020405 started about 1 day after the GRB and extended over ~70 days. Photometry shows that the early decay is consistent with a singly power law of index α = 1.54±0.06 in all bands. The late epoch light curves, sampled with HST and VLT, exhibit a plateau or slight rebrightening around 10-20 days after the GRB. This bump can be modeled with a SN2002ap template underlying the afterglow. Alternatively, the late-epoch data can also be fitted using a power law with index steeper (α′ = 1.85±0.15) than that of the early decay phase, in agreement with a late shell collision interpretation. Spectroscopy indicates that the GRB is at z = 0.691 and that the host galaxy complex is angularly close to a system of at least two galaxies at z = 0.472. R-band polarimetry shows that the afterglow is polarized, with P = 1.5±0.4 % and polarization angle θ = 172°±8°. |
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