Examinando por Autor "Pian, Elena"

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    A missing-link in the supernova-GRB connection: The case of SN 2012ap
    (Institute of Physics Publishing, 2015-06) Chakraborti, Sayan; Soderberg, Alicia; Chomiuk, Laura; Kamble, Atish; Yadav, Naveen; Ray, Alak; Hurley, Kevin; Margutti, Raffaella; Milisavljevic, Dan; Bietenholz, Michael; Brunthaler, Andreas; Pignata, Giuliano; Pian, Elena; Mazzali, Paolo; Fransson, Claes; Bartel, Norbert; Hamuy, Mario; Levesque, Emily; Macfadyen, Andrew; Dittmann, Jason; Krauss, Miriam; Briggs, M.S.; Connaughton, V.; Yamaoka, K.; Takahashi, T.; Ohno M., Fukazawa; Tashiro, M.; Terada, Y.; Murakami, T.; Goldsten, J.; Barthelmy, S.; Gehrels, N.; Cummings, J.; Krimm, H.; Palmer, D.; Golenetskii, S.; Aptekar, R.; Frederiks, D.; Svinkin, D.; Cline, T.; Mitrofanov, I.G.; Golovin, D.; Litvak, M.L.; Sanin, A.B.; Boynton, W.; Fellows, C.; Harshman, K.; Enos, H.; Kienlin, A. Von; Rau, A.; Zhang, X.; Savchenko, V.
    Gamma-ray bursts (GRBs) are characterized by ultra-relativistic outflows, while supernovae are generally characterized by non-relativistic ejecta. GRB afterglows decelerate rapidly, usually within days, because their low-mass ejecta rapidly sweep up a comparatively larger mass of circumstellar material. However, supernovae with heavy ejecta can be in nearly free expansion for centuries. Supernovae were thought to have non-relativistic outflows except for a few relativistic ones accompanied by GRBs. This clear division was blurred by SN 2009bb, the first supernova with a relativistic outflow without an observed GRB. However, the ejecta from SN 2009bb was baryon loaded and in nearly free expansion for a year, unlike GRBs. We report the first supernova discovered without a GRB but with rapidly decelerating mildly relativistic ejecta, SN 2012ap. We discovered a bright and rapidly evolving radio counterpart driven by the circumstellar interaction of the relativistic ejecta. However, we did not find any coincident GRB with an isotropic fluence of more than one-sixth of the fluence from GRB 980425. This shows for the first time that central engines in SNe Ic, even without an observed GRB, can produce both relativistic and rapidly decelerating outflows like GRBs. © 2015. The American Astronomical Society. All rights reserved.
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    A very luminous magnetar-powered supernova associated with an ultra-long γ-ray burst
    (Nature Publishing Group, 2015-07) Greiner, Jochen; Mazzali, Paolo A.; Kann, D. Alexander; Krühler, Thomas; Pian, Elena; Prentice, Simon; Olivares, E.; Rossi, Andrea; Klose, Sylvio; Taubenberger, Stefan; Knust, Fabian; Afonso, Paulo; Ashall, Chris; Bolmer, Jan; Delvaux, Corentin; Diehl, Roland; Elliott, Jonathan; Filgas, Robert; Fynbo, Johan P.U.; Graham, John F.; Guelbenzu, Ana Nicuesa; Kobayashi, Shiho; Leloudas, Giorgos; Savaglio, Sandra; Schady, Patricia; Schmidl, Sebastian; Schweyer, Tassilo; Sudilovsky, Vladimir; Tanga, Mohit; Updike, Adria C.; Van Eerten, Hendrik; Varela, Karla
    A new class of ultra-long-duration (more than 10,000 seconds) γ-ray bursts has recently been suggested. They may originate in the explosion of stars with much larger radii than those producing normal long-duration γ-ray bursts or in the tidal disruption of a star. No clear supernova has yet been associated with an ultra-long-duration γ-ray burst. Here we report that a supernova (SN 2011kl) was associated with the ultra-long-duration γ-ray burst GRB 111209A, at a redshift z of 0.677. This supernova is more than three times more luminous than type Ic supernovae associated with long-duration γ-ray bursts, and its spectrum is distinctly different. The slope of the continuum resembles those of super-luminous supernovae, but extends further down into the rest-frame ultraviolet implying a low metal content. The light curve evolves much more rapidly than those of super-luminous supernovae. This combination of high luminosity and low metal-line opacity cannot be reconciled with typical type Ic supernovae, but can be reproduced by a model where extra energy is injected by a strongly magnetized neutron star (a magnetar), which has also been proposed as the explanation for super-luminous supernovae. © 2015 Macmillan Publishers Limited. All rights reserved.
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    The Highly Energetic Expansion of SN2010bh Associated with GRB100316D
    (2012) Bufano, Filomena; Pian, Elena; Sollerman, Jesper; Benetti, Stefano; Pignata, Giuliano; Valenti, Stefano; Covino, Stefano; D’Avanzo, Paolo; Malesani, Daniele; Enrico, Cappellaro; Della Valle, Massimo; Fynbo, Johan; Hjorth, Jens; Mazzali, Paolo A.; Reichart, Daniel E.; Starling, Rhaana L. C.; Turatto, Massimo; Vergani, Susanna D.; Wiersema, Klass; Amati, Lorenzo; Bersier, David; Campana, Sergio; Cano, Zach; Castro-Tirado, Alberto J.; Chincarini, Guido; D’Elia, Valerio; de Ugarte, Antonio; Postigo, Deng, Jinsong; Ferrero, Patrizia; Alexei V., Filippenko; Goldoni, Paolo; Gorosabel, Javier; Greiner, Jochen; Hammer, Francois; Jakobsson, Pall; Kaper, Lex; Kawabata, Koji S.; Klose, Sylvio; Levan, Andrew J.; Maeda, Keiichi; Masetti, Nicola; Milvang-Jensen, Bo; Mirabel, Felix I.; Moller, Palle; Nomoto, Ken’ichi; Palazzi, Eliana; Piranomonte, Silvia; Salvaterra, Ruben; Stratta, Giulia; Tagliaferri, Gianpiero; Tanaka, Masaomi; Tanvir, Nial R.; Wijers, Ralph A.M.J.