Examinando por Autor "Perego, A."

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    A comparison between short GRB afterglows and kilonova AT2017gfo: Shedding light on kilonovae properties
    (Oxford University Press, 2020-04) Rossi, A.; Stratta, G.; Maiorano, E.; Spighi, D.; Masetti, N.; Palazzi, E.; Gardini, A.; Melandri, A.; Nicastro, L.; Pian, E.; Branchesi, M.; Dadina, M.; Testa, V.; Brocato, E.; Benetti, S.; Ciolfi, R.; Covino, S.; D'Elia, V.; Grado, A.; Izzo, L.; Perego, A.; Piranomonte, S.; Salvaterra, R.; Selsing, J.; Tomasella, L.; Yang, S.; Vergani, D.; Amati, L.; Stephen, J.B.
    Multimessenger astronomy received a great boost following the discovery of kilonova (KN) AT2017gfo, the optical counterpart of the gravitational wave source GW170817 associated with the short gamma-ray burst GRB 170817A. AT2017gfo was the first KN that could be extensively monitored in time using both photometry and spectroscopy. Previously, only few candidates have been observed against the glare of short GRB afterglows. In this work, we aim to search the fingerprints of AT2017gfo-like KN emissions in the optical/NIR light curves of 39 short GRBs with known redshift. For the first time, our results allow us to study separately the range of luminosity of the blue and red components of AT2017gfo-like kilonovae in short GRBs. In particular, the red component is similar in luminosity to AT2017gfo, while the blue KN can be more than 10 times brighter. Finally, we exclude a KN as luminous as AT2017gfo in GRBs 050509B and 061201. © 2020 The Author(s).
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    The Peculiar Short-duration GRB 200826A and Its Supernova
    (Institute of Physics, 2022-06-01) Rossi, A.; Rothberg, B.; Palazzi, E.; Kann, D.A.; D'Avanzo, P.; Amati, L.; Klose, S.; Perego, A.; Pian, E.; Guidorzi, C.; Pozanenko, A.S.; Savaglio, S.; Stratta, G.; Agapito, G.; Covino, S.; Cusano, F.; D'Elia, V.; Pasquale, M. De; Valle, M. Della; Kuhn, O.; Izzo, L.; Loffredo, E.; Masetti, N.; Melandri, A.; Minaev, P.Y.; Guelbenzu, A. Nicuesa; Paris, D.; Paiano, S.; Plantet, C.; Rossi, F.; Salvaterra, R.; Schulze, S.; Veillet, C.; Volnova, A.A.
    Gamma-ray bursts (GRBs) are classified into long and short events. Long GRBs (LGRBs) are associated with the end states of very massive stars, while short GRBs (SGRBs) are linked to the merger of compact objects. GRB 200826A was a peculiar event, because by definition it was an SGRB, with a rest-frame duration of 1/40.5 s. However, this event was energetic and soft, which is consistent with LGRBs. The relatively low redshift (z = 0.7486) motivated a comprehensive, multiwavelength follow-up campaign to characterize its host, search for a possible associated supernova (SN), and thus understand the origin of this burst. To this aim we obtained a combination of deep near-infrared (NIR) and optical imaging together with spectroscopy. Our analysis reveals an optical and NIR bump in the light curve whose luminosity and evolution are in agreement with several SNe associated to LGRBs. Analysis of the prompt GRB shows that this event follows the E p,i-E iso relation found for LGRBs. The host galaxy is a low-mass star-forming galaxy, typical of LGRBs, but with one of the highest star formation rates, especially with respect to its mass ( logM∗/M⊙=8.6, SFR ∼4.0 M ⊙ yr-1). We conclude that GRB 200826A is a typical collapsar event in the low tail of the duration distribution of LGRBs. These findings support theoretical predictions that events produced by collapsars can be as short as 0.5 s in the host frame and further confirm that duration alone is not an efficient discriminator for the progenitor class of a GRB. © 2022. The Author(s). Published by the American Astronomical Society.