Examinando por Autor "Brown P.J."

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    A long life of excess: The interacting transient SN 2017hcc
    (EDP Sciences, 2023-01) Moran S.; Fraser M.; Kotak R.; Pastorello A.; Benetti S.; Brennan S.J.; Gutiérrez C.P.; Kankare E.; Kuncarayakti H.; Mattila S.; Reynolds T.M.; Anderson J.P.; Brown P.J.; Campana S.; Chambers K.C.; Chen T.-W.; Della Valle M.; Dennefeld M.; Elias-Rosa N.; Galbany L.; Galindo-Guil F.J.; Gromadzki M.; Hiramatsu D.; Inserra C.; Leloudas G.; Müller-Bravo T.E.; Nicholl M.; Reguitti A.; Shahbandeh M.; Smartt S.J.; Tartaglia L.; Young D.R.
    In this study we present the results of a five-year follow-up campaign of the long-lived type IIn supernova SN 2017hcc, found in a spiral dwarf host of near-solar metallicity. The long rise time (57 ± 2 days, ATLAS o band) and high luminosity (peaking at -20.78 ± 0.01 mag in the ATLAS o band) point towards an interaction of massive ejecta with massive and dense circumstellar material (CSM). The evolution of SN 2017hcc is slow, both spectroscopically and photometrically, reminiscent of the long-lived type IIn, SN 2010jl. An infrared (IR) excess was apparent soon after the peak, and blueshifts were noticeable in the Balmer lines starting from a few hundred days, but appeared to be fading by around +1200 d. We posit that an IR light echo from pre-existing dust dominates at early times, with some possible condensation of new dust grains occurring at epochs ≳;+800 d. © The Authors 2023.
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    SN 2017gmr: An Energetic Type II-P Supernova with Asymmetries
    (Institute of Physics Publishing, 2019-11-01) Andrews, Jennifer E.; Sand D.J.; Valenti S.; Smith, Nathan; Dastidar, Raya; Sahu D.K.; Misra, Kuntal; Singh, Avinash; Hiramatsu D.; Brown P.J.; Hosseinzadeh G.; Wyatt S.; Vinko J.; Anupama G.C.; Arcavi I.; Ashall, Chris; Benetti S.; Berton, Marco; Bostroem K.A.; Bulla M.; Burke J.; Chen S.; Chomiuk L.; Cikota A.; Congiu E.; Cseh B.; Davis, Scott; Elias-Rosa N.; Faran T.; Fraser, Morgan; Galbany L.; Gall C.; Gal-Yam A.; Gangopadhyay, Anjasha; Gromadzki M.; Haislip J.; Howell D.A.; Hsiao E.Y.; Inserra C.; Kankare E.; Kuncarayakti H.; Kouprianov V.; Kumar, Brajesh; Li, Xue; Lin, Han; Maguire K.; Mazzali P.; McCully C.; Milne P.; Mo, Jun; Morrell N.; Nicholl M.; Ochner P.; Olivares F.; Pastorello A.; Patat F.; Phillips M.; Pignata G.; Prentice S.; Reguitti A.; Reichart D.E.; Rodríguez Ó.; Rui, Liming; Sanwal, Pankaj; Sárneczky K.; Shahbandeh M.; Singh, Mridweeka; Smartt S.; Strader J.; Stritzinger M.D.; Szakáts R.; Tartaglia L.; Wang, Huijuan; Wang, Lingzhi; Wang, Xiaofeng; Wheeler J.C.; Xiang, Danfeng; Yaron O.; Young D.R.; Zhang, Junbo
    We present high-cadence UV, optical, and near-infrared data on the luminous Type II-P supernova SN 2017gmr from hours after discovery through the first 180 days. SN 2017gmr does not show signs of narrow, high-ionization emission lines in the early optical spectra, yet the optical light-curve evolution suggests that an extra energy source from circumstellar medium (CSM) interaction must be present for at least 2 days after explosion. Modeling of the early light curve indicates a ∼500 R o progenitor radius, consistent with a rather compact red supergiant, and late-time luminosities indicate that up to 0.130 ± 0.026 M o of 56Ni are present, if the light curve is solely powered by radioactive decay, although the 56Ni mass may be lower if CSM interaction contributes to the post-plateau luminosity. Prominent multipeaked emission lines of Hα and [O i] emerge after day 154, as a result of either an asymmetric explosion or asymmetries in the CSM. The lack of narrow lines within the first 2 days of explosion in the likely presence of CSM interaction may be an example of close, dense, asymmetric CSM that is quickly enveloped by the spherical supernova ejecta.