Examinando por Autor "de Ugarte Postigo, A."

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    GRB 171010A/SN 2017htp: A Grb-Sn at z = 0.33
    (Oxford University Press, 2019-12) Melandri, A.; Malesani, D.B.; Izzo, L.; Japelj, J.; Vergani, S.D.; Schady, P.; Sagués Carracedo, A.; de Ugarte Postigo, A.; Anderson, J.P.; Barbarino, C.; Bolmer, J.; Breeveld, A.; Calissendorff, P.; Campana, S.; Cano, Z.; Carini, R.; Covino, S.; D'Avanzo, P.; D'Elia, V.; della Valle, M.; de Pasquale, M.; Fynbo, J.P.U.; Gromadzki, M.; Hammer, F.; Hartmann, D.H.; Heintz, K.E.; Inserra, C.; Jakobsson, P.; Kann, D.A.; Kotilainen, J.; Maguire, K.; Masetti, N.; Nicholl, M.; Olivares, F.E.; Pugliese, G.; Rossi, A.; Salvaterra, R.; Sollerman, J.; Stone, M.B.; Tagliaferri, G.; Tomasella, L.; Thöne, C.C.; Xu, D.; Young, D.R.
    The number of supernovae known to be connected with long-duration gamma-ray bursts (GRBs) is increasing and the link between these events is no longer exclusively found at low redshift (z ≲ 0.3) but is well established also at larger distances. We present a new case of such a liaison at z = 0.33 between GRB 171010A and SN 2017htp. It is the second closest GRB with an associated supernova of only three events detected by Fermi-LAT. The supernova is one of the few higher redshift cases where spectroscopic observations were possible and shows spectral similarities with the well-studied SN 1998bw, having produced a similar Ni mass (⁠MNi=0.33±0.02 M⊙ ⁠) with slightly lower ejected mass (⁠Mej=4.1±0.7 M⊙ ⁠) and kinetic energy (⁠EK=8.1±2.5×1051 erg ⁠). The host-galaxy is bigger in size than typical GRB host galaxies, but the analysis of the region hosting the GRB revealed spectral properties typically observed in GRB hosts and showed that the progenitor of this event was located in a very bright H II region of its face-on host galaxy, at a projected distance of ∼ 10 kpc from its galactic centre. The star-formation rate (SFRGRB ∼ 0.2 M⊙ yr−1) and metallicity (12 + log(O/H) ∼8.15 ± 0.10) of the GRB star-forming region are consistent with those of the host galaxies of previously studied GRB–SN systems.
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    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.