A. Melandri, E. Pian, P. Ferrero, P. D'Avanzo, E. S. Walker, G. Ghirlanda, S. Covino, L. Amati, V. D'Elia, P. A. Mazzali, M. Della Valle, C. Guidorzi, L. A. Antonelli, M. G. Bernardini, F. Bufano, S. Campana, A. J. Castro-Tirado, G. Chincarini, J. Deng, A. V. Filippenko, D. Fugazza, G. Ghisellini, C. Kouveliotou, K. Maeda, G. Marconi, N. Masetti, K. Nomoto, E. Palazzi, F. Patat, S. Piranomonte, R. Salvaterra, I. Saviane, R. L. C. Starling, G. Tagliaferri, M. Tanaka, S. D. Vergani
The association of Type Ic supernovae (SNe) with long-duration gamma-ray bursts (GRB) is well established. GRB 120422A was a low-redshift (z=0.283) event that allowed an extensive ground-based observational campaign to monitor the light curve of the associated SN 2012bz. We obtained a series of photometric and spectroscopic observations of SN 2012bz associated with the long-duration GRB 120422A using the 3.6-m TNG and the 8.2-m VLT telescopes during the time interval between 4 and 36 days after the burst. We characterized the optical light curve of SN 2012bz and compared its shape with other GRB/SNe. Peak brightness was reached ~18 days after the burst, corresponding to ~14 days in the rest-frame. A general resemblance between the spectra of SN 2012bz and SN 1998bw at similar epochs is noticed, but the spectra are too noisy for detailed analysis. The shape and maximum of the bolometric light curve (M ~ -18.7) are very similar to those of other known GRB/SNe, suggesting comparable explosion conditions and parameters. GRB 120422A may lie slightly above the 2\sigma confidence region of the Epeak-Eiso relation.
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http://arxiv.org/abs/1206.5532
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