Examinando por Autor "Kann, D. A."

Mostrando 1 - 2 de 2
  • No hay miniatura disponible
    Ítem
    Highly luminous supernovae associated with gamma-ray bursts: I. GRB 111209A/SN 2011kl in the context of stripped-envelope and superluminous supernovae
    (Astronomy and Astrophysics, 2019-04-01) Kann, D. A.; Schady, P.; Olivares E., F.; Klose, S.; Rossi, A.; Perley, D. A.; Krühler, T.; Greiner, J.; Nicuesa Guelbenzu, A.; Elliott, J.; Knust, F.; Filgas, R.; Pian, E.; Mazzali, P.; Fynbo, J. P. U.; Leloudas, G.; Afonso, P. M. J.; Delvaux, C.; Graham, J. F.; Rau, A.; Schmidl, S.; Schulze, S.; Tanga, M.; Updike, A. C.; Varela, K.
    Context. GRB 111209A, one of the longest gamma-ray bursts (GRBs) ever observed, is linked to SN 2011kl, which is the most luminous GRB supernova (SN) detected so far. Several lines of evidence indicate that this GRB-SN is powered by a magnetar central engine. Aims. We place SN 2011kl into the context of large samples of SNe, addressing in more detail the question of whether this GRB-SN could be radioactively powered, and whether it represents an extreme version of a GRB-SN or an underluminous superluminous SN (SLSN). Methods. We modelled SN 2011kl using SN 1998bw as a template and derived a bolometric light curve including near-infrared data. We compared the properties of SN 2011kl to literature results on stripped-envelope and SLSNe. Results. A comparison in the k,- s context, i.e. comparing SN 2011kl to SN 1998bw templates in terms of luminosity and light-curve stretch, clearly shows SN 2011kl is the most luminous GRB-SN to date and is spectrally very dissimilar to other events because it is significantly bluer/hotter. Although SN 2011kl does not reach the classical luminosity threshold of SLSNe and evolves faster than any of these objects, it resembles SLSNe more than the classical GRB-associated broad-lined Type Ic SNe in several aspects. Conclusions. GRB 111209A was a very energetic event, both at early (prompt emission) and at very late (SN) times. We show in a companion publication that with the exception of the extreme duration, the GRB and afterglow parameters are in agreement with the known distributions for these parameters. SN 2011kl, on the other hand, is exceptional both in luminosity and spectral characteristics, indicating that GRB 111209A was likely not powered by a standard-model collapsar central engine, further supporting our earlier conclusions. Instead, it reveals the possibility of a direct link between GRBs and SLSNe.
  • No hay miniatura disponible
    Ítem
    The evolution of luminous red nova AT 2017jfs in NGC 4470
    (Astronomy and Astrophysics, 2019) Pastorello, A.; Chen, T.W.; Cai, Y. Z.; Morales-Garoffolo, A.; Cano, Z.; Mason, E.; Barsukova, E. A.; Benetti, S.; Berton, M.; Bose, S.; Bufano, F.; Callis, E.; Cannizzaro, G.; Cartier, R.; Chen, Ping; Dong, Subo; Dyrbye, S.; Elias-Rosa, N.; Flörs, A.; Fraser, M.; Geier, S.; Goranskij, V. P.; Kann, D. A.; Kuncarayakti, H.; Onori, F.; Reguitti, A.; Reynolds, T.; Losada, I. R.; Sagués Carracedo, A.; Schweyer, T.; Smartt, S. J.; Tatarnikov, A. M.; Valeev, A. F.; Vogl, C.; Wevers, T.; de Ugarte Postigo, A.; Izzo, L.; Inserra, C.; Kankare, E.; Maguire, K.; Smith, K. W.; Stalder, B.; Tartaglia, L.; Thöne, C. C.; Valerin, G.; Young, D. R.
    We present the results of our photometric and spectroscopic follow-up of the intermediate-luminosity optical transient AT 2017jfs. At peak, the object reaches an absolute magnitude of Mg = -15:46 ± 0:15 mag and a bolometric luminosity of 5:5 × 1041 erg s-1. Its light curve has the doublepeak shape typical of luminous red novae (LRNe), with a narrow first peak bright in the blue bands, while the second peak is longer-lasting and more luminous in the red and near-infrared (NIR) bands. During the first peak, the spectrum shows a blue continuum with narrow emission lines of H and Fe II. During the second peak, the spectrum becomes cooler, resembling that of a K-type star, and the emission lines are replaced by a forest of narrow lines in absorption. About 5 months later, while the optical light curves are characterized by a fast linear decline, the NIR ones show a moderate rebrightening, observed until the transient disappears in solar conjunction. At these late epochs, the spectrum becomes reminiscent of that of M-type stars, with prominent molecular absorption bands. The late-time properties suggest the formation of some dust in the expanding common envelope or an IR echo from foreground pre-existing dust. We propose that the object is a common-envelope transient, possibly the outcome of a merging event in a massive binary, similar to NGC4490-2011OT1.