Cano, Z.; Bersier, D.; Guidorzi, C.; Margutti, R.; Svensson, K. M.; Kobayashi, S.; Melandri, A.; Wiersema, K.; Pozanenko, A.; van der Horst, A. J.; Pooley, G. G.; Fernandez-Soto, A.; Castro-Tirado, A. J.; Postigo, A. De Ugarte; Im, M.; Kamble, A. P.; Sahu, D.; Alonso-Lorite, J.; Anupama, G.; Bibby, J. L.; Burgdorf, M. J.; Clay, N.; Curran, P. A.; Fatkhullin, T. A.; Fruchter, A. S.; Garnavich, P.; Gomboc, A.; Gorosabel, J.; Graham, J. F.; Gurugubelli, U.; Haislip, J.; Huang, K.; Huxor, A.; Ibrahimov, M.; Jeon, Y.; Jeon, Y.-B.; Ivarsen, K.; Kasen, D.; Klunko, E.; Kouveliotou, C.; Lacluyze, A.; Levan, A. J.; Loznikov, V.; Mazzali, P. A.; Moskvitin, A. S.; Mottram, C.; Mundell, C. G.; Nugent, P. E.; Nysewander, M.; O'Brien, P. T.; Park, W.-K.; Peris, V.; Pian, E.; Reichart, D.; Rhoads, J. E.; Rol, E.; Rumyantsev, V.; Scowcroft, V.; Shakhovskoy, D.; Small, E.; Smith, R. J.; Sokolov, V. V.; Starling, R. L. C.; Steele, I.; Strom, R. G.; Tanvir, N. R.; Tsapras, Y.; Urata, Y.; Vaduvescu, O.; Volnova, A.; Volvach, A.; Wijers, R. A. M. J.; Woosley, S. E.; Young, D. R.
Bibliographical reference
Monthly Notices of the Royal Astronomical Society, Volume 413, Issue 1, pp. 669-685.
Advertised on:
5
2011
Citations
89
Refereed citations
78
Description
We present ground-based and Hubble Space Telescope optical observations
of the optical transients (OTs) of long-duration Gamma Ray Bursts (GRBs)
060729 and 090618, both at a redshift of z= 0.54. For GRB 060729, bumps
are seen in the optical light curves (LCs), and the late-time broad-band
spectral energy distributions (SEDs) of the OT resemble those of local
Type Ic supernovae (SNe). For GRB 090618, the dense sampling of our
optical observations has allowed us to detect well-defined bumps in the
optical LCs, as well as a change in colour, that are indicative of light
coming from a core-collapse SN. The accompanying SNe for both events are
individually compared with SN1998bw, a known GRB supernova, and SN1994I,
a typical Type Ic supernova without a known GRB counterpart, and in both
cases the brightness and temporal evolution more closely resemble
SN1998bw. We also exploit our extensive optical and radio data for GRB
090618, as well as the publicly available Swift-XRT data, and discuss
the properties of the afterglow at early times. In the context of a
simple jet-like model, the afterglow of GRB 090618 is best explained by
the presence of a jet-break at t-to > 0.5 d. We then
compare the rest-frame, peak V-band absolute magnitudes of all of the
GRB and X-Ray Flash (XRF)-associated SNe with a large sample of local
Type Ibc SNe, concluding that, when host extinction is considered, the
peak magnitudes of the GRB/XRF-SNe cannot be distinguished from the peak
magnitudes of non-GRB/XRF SNe.