Examinando por Autor "Elias Rosa, N."
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Ítem Low luminosity Type II supernovae - IV. SN 2020cxd and SN 2021aai, at the edges of the sub-luminous supernovae class(Oxford University Press, 2022-07-01) Valerin, G.; Pumo, M.L.; Pastorello, A.; Reguitti, A.; Elias Rosa, N.; Gútierrez, C.P.; Kankare, E.; Fraser, M.; Mazzali, P.A.; Howell, D.A.; Kotak, R.; Galbany, L.Photometric and spectroscopic data for two Low Luminosity Type IIP Supernovae (LL SNe IIP) 2020cxd and 2021aai are presented. SN 2020cxd was discovered 2 d after explosion at an absolute magnitude of Mr = -14.02 ± 0.21 mag, subsequently settling on a plateau which lasts for ∼120 d. Through the luminosity of the late light curve tail, we infer a synthesized 56Ni mass of (1.8 ± 0.5) × 10-3 M⊙. During the early evolutionary phases, optical spectra show a blue continuum ($T\, \gt $8000 K) with broad Balmer lines displaying a P Cygni profile, while at later phases, Ca ii, Fe ii, Sc ii, and Ba ii lines dominate the spectra. Hydrodynamical modelling of the observables yields $R\, \simeq$ 575 R⊙ for the progenitor star, with Mej = 7.5 M⊙ and $E\, \simeq$ 0.097 foe emitted during the explosion. This low-energy event originating from a low-mass progenitor star is compatible with both the explosion of a red supergiant (RSG) star and with an Electron Capture Supernova arising from a super asymptotic giant branch star. SN 2021aai reaches a maximum luminosity of Mr = -16.57 ± 0.23 mag (correcting for AV = 1.92 mag), at the end of its remarkably long plateau (∼140 d). The estimated 56Ni mass is (1.4 ± 0.5) × 10-2 M⊙. The expansion velocities are compatible with those of other LL SNe IIP (few 103 km s-1). The physical parameters obtained through hydrodynamical modelling are $R\, \simeq$ 575 R⊙, Mej = 15.5 M⊙, and E = 0.4 foe. SN 2021aai is therefore interpreted as the explosion of an RSG, with properties that bridge the class of LL SNe IIP with standard SN IIP events. © 2022 The Author(s).Ítem Photometric and spectroscopic evolution of the interacting transient at 2016jbu(Gaia16cfr)(Oxford University Press, 2022-07-01) Brennan, S.J.; Fraser, M.; Johansson, J.; Pastorello, A.; Kotak, R.; Stevance, H.F.; Chen, T.-W.; Eldridge, J.J.; Bose, S.; Brown, P.J.; Callis, E.; Cartier, R.; Dennefeld, M.; Dong, Subo; Duffy, P.; Elias Rosa, N.; Hosseinzadeh, G.; Hsiao, E.; Kuncarayakti, H.; Martin Carrillo, A.; Monard, B.; Nyholm, A.; Pignata, G.; Sand, D.; Shappee, B.J.; Smartt, S.J.; Tucker, B.E.; Wyrzykowski, L.; Abbot, H.; Benetti, S.; Bento, J.; Blondin, S.; Chen, Ping; Delgado, A.; Galbany, L.; Gromadzki, M.; Gutierrez, C.P.; Hanlon, L.; Harrison, D.L.; Hiramatsu, D.; Hodgkin, S.T.; Holoien, T.W.-S.; Howell, D.A.; Inserra, C.; Kankare, E.; Kozłowski, S.; Müller Bravo, T.E.; Maguire, K.; McCully, C.; Meintjes, P.; Morrell, N.; Nicholl, M.; O'Neill, D.; Pietrukowicz, P.; Poleski, R.; Prieto, J.L.; Rau, A.; Reichart, D.E.; Schweyer, T.; Shahbandeh, M.; Skowron, J.; Sollerman, J.; Soszyński, I.; Stritzinger, M.D.; Szymański, M.; Tartaglia, L.; Udalski, A.; Ulaczyk, K.; Young, D.R.; Van Leeuwen, M.; Van Soelen, B.We present the results from a high-cadence, multiwavelength observation campaign of AT 2016jbu (aka Gaia16cfr), an interacting transient. This data set complements the current literature by adding higher cadence as well as extended coverage of the light-curve evolution and late-time spectroscopic evolution. Photometric coverage reveals that AT 2016jbu underwent significant photometric variability followed by two luminous events, the latter of which reached an absolute magnitude of MV ∼-18.5 mag. This is similar to the transient SN 2009ip whose nature is still debated. Spectra are dominated by narrow emission lines and show a blue continuum during the peak of the second event. AT 2016jbu shows signatures of a complex, non-homogeneous circumstellar material (CSM). We see slowly evolving asymmetric hydrogen line profiles, with velocities of 500 km s-1 seen in narrow emission features from a slow-moving CSM, and up to 10 000 km s-1 seen in broad absorption from some high-velocity material. Late-time spectra (∼+1 yr) show a lack of forbidden emission lines expected from a core-collapse supernova and are dominated by strong emission from H, He i, and Ca ii. Strong asymmetric emission features, a bumpy light curve, and continually evolving spectra suggest an inhibit nebular phase. We compare the evolution of H α among SN 2009ip-like transients and find possible evidence for orientation angle effects. The light-curve evolution of AT 2016jbu suggests similar, but not identical, circumstellar environments to other SN 2009ip-like transients. © 2022 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society.Ítem Progenitor, environment, and modelling of the interacting transient AT 2016jbu (Gaia16cfr)(Oxford University Press, 2022-07-01) Brennan, S.J.; Fraser, M.; Johansson, J.; Pastorello, A.; Kotak, R.; Stevance, H.F.; Chen, T.-W.; Eldridge, J.J.; Bose, S.; Brown, P.J.; Callis, E.; Cartier, R.; Dennefeld, M.; Dong, Subo; Duffy, P.; Elias Rosa, N.; Hosseinzadeh, G.; Hsiao, E.; Kuncarayakti, H.; Martin Carrillo, A.; Monard, B.; Pignata, G.; Sand, D.; Shappee, B.J.; Smartt, S.J.; Tucker, B.E.; Wyrzykowski, L.; Abbot, H.; Benetti, S.; Bento, J.; Blondin, S.; Chen, Ping; Delgado, A.; Galbany, L.; Gromadzki, M.; Gutierrez, C.P.; Hanlon, L.; Harrison, D.L.; Hiramatsu, D.; Hodgkin, S.T.; Holoien, T.W.-S.; Howell, D.A.; Inserra, C.; Kankare, E.; Kozłowski, S.; Müller Bravo, T.E.; Maguire, K.; Mccully, C.; Meintjes, P.; Morrell, N.; Nicholl, M.; O'neill, D.; Pietrukowicz, P.; Poleski, R.; Prieto, J.L.; Rau, A.; Reichart, D.E.; Schweyer, T.; Shahbandeh, M.; Skowron, J.; Sollerman, J.; Soszyński, I.; Stritzinger, M.D.; Szymański, M.; Tartaglia, L.; Udalski, A.; Ulaczyk, K.; Young, D.R.; Van Leeuwen, M.; Van Soelen, B.We present the bolometric light curve, identification and analysis of the progenitor candidate, and preliminary modelling of AT 2016jbu (Gaia16cfr). We find a progenitor consistent with a ∼22-25 M⊙ yellow hypergiant surrounded by a dusty circumstellar shell, in agreement with what has been previously reported. We see evidence for significant photometric variability in the progenitor, as well as strong Hα emission consistent with pre-existing circumstellar material. The age of the environment, as well as the resolved stellar population surrounding AT 2016jbu, supports a progenitor age of >10 Myr, consistent with a progenitor mass of ∼22 M⊙. A joint analysis of the velocity evolution of AT 2016jbu and the photospheric radius inferred from the bolometric light curve shows the transient is consistent with two successive outbursts/explosions. The first outburst ejected material with velocity ∼650 km s-1, while the second, more energetic event ejected material at ∼4500 km s-1. Whether the latter is the core collapse of the progenitor remains uncertain. We place a limit on the ejected 56Ni mass of [removed]Ítem SN 2020acat: an energetic fast rising Type IIb supernova(Oxford University Press, 2022-07-01) Medler, K.; Mazzali, P.A.; Teffs, J.; Ashall, C.; Anderson, J.P.; Arcavi, I.; Benetti, S.; Bostroem, K.A.; Burke, J.; Cai, Y.-Z.; Charalampopoulos, P.; Elias Rosa, N.; Ergon, M.; Galbany, L.; Gromadzki, M.; Hiramatsu, D.; Howell, D.A.; Inserra, C.; Lundqvist, P.; McCully, C.; Müller Bravo, T.; Newsome, M.; Nicholl, M.; Gonzalez, E. Padilla; Paraskeva, E.; Pastorello, A.; Pellegrino, C.; Pessi, P.J.; Reguitti, A.; Reynolds, T.M.; Roy, R.; Terreran, G.; Tomasella, L.; Young, D.R.The ultraviolet (UV) and near-infrared (NIR) photometric and optical spectroscopic observations of SN 2020acat covering ∼250 d after explosion are presented here. Using the fast rising photometric observations, spanning from the UV to NIR wavelengths, a pseudo-bolometric light curve was constructed and compared to several other well-observed Type IIb supernovae (SNe IIb). SN 2020acat displayed a very short rise time reaching a peak luminosity of Log10(L) = 42.49 ± 0.17 erg s-1 in only ∼14.6 ± 0.3 d. From modelling of the pseudo-bolometric light curve, we estimated a total mass of 56Ni synthesized by SN 2020acat of MNi = 0.13 ± 0.03 M⊙, with an ejecta mass of Mej = 2.3 ± 0.4 M⊙ and a kinetic energy of Ek = 1.2 ± 0.3 × 1051 erg. The optical spectra of SN 2020acat display hydrogen signatures well into the transitional period (≳ 100 d), between the photospheric and the nebular phases. The spectra also display a strong feature around 4900 Å that cannot be solely accounted for by the presence of the Fe ii 5018 line. We suggest that the Fe ii feature was augmented by He i 5016 and possibly by the presence of N ii 5005. From both photometric and spectroscopic analysis, we inferred that the progenitor of SN 2020acat was an intermediate-mass compact star with an MZAMS of 15-20 M⊙. © 2022 The Author(s).