Examinando por Autor "Kuncarayakti H."
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Ítem 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.Ítem Photometry and spectroscopy of the Type Icn supernova 2021ckj: The diverse properties of the ejecta and circumstellar matter of Type Icn supernovae(EDP Sciences, 2023-05) Nagao T.; Kuncarayakti H.; Maeda K.; Moore T.; Pastorello A.; Mattila S.; Uno K.; Smartt S.J.; Sim S.A.; Ferrari L.; Tomasella L.; Anderson J.P.; Chen T.-W.; Galbany L.; Gao H.; Gromadzki M.; Gutiérrez C.P.; Inserra C.; Kankare E.; Magnier E.A.; Müller-Bravo T.E.; Reguitti A.; Young D.R.We present photometric and spectroscopic observations of the Type Icn supernova (SN) 2021ckj. This rare type of SNe is characterized by a rapid evolution and high peak luminosity as well as narrow lines of highly ionized carbon at early phases, implying an interaction with hydrogen- and helium-poor circumstellar matter (CSM). SN 2021ckj reached a peak brightness of ~-20 mag in the optical bands, with a rise time and a time above half maximum of ~4 and ~10 days, respectively, in the g and cyan bands. These features are reminiscent of those of other Type Icn SNe (SNe 2019hgp, 2021csp, and 2019jc), with the photometric properties of SN 2021ckj being almost identical to those of SN 2021csp. Spectral modeling of SN 2021ckj reveals that its composition is dominated by oxygen, carbon, and iron group elements, and the photospheric velocity at peak is ~10000 km s-1. Modeling the spectral time series of SN 2021ckj suggests aspherical SN ejecta. From the light curve (LC) modeling applied to SNe 2021ckj, 2019hgp, and 2021csp, we find that the ejecta and CSM properties of Type Icn SNe are diverse. SNe 2021ckj and 2021csp likely have two ejecta components (an aspherical high-energy component and a spherical standard-energy component) with a roughly spherical CSM, while SN 2019hgp can be explained by a spherical ejecta-CSM interaction alone. The ejecta of SNe 2021ckj and 2021csp have larger energy per ejecta mass than the ejecta of SN 2019hgp. The density distribution of the CSM is similar in these three SNe, and is comparable to those of Type Ibn SNe. This may imply that the mass-loss mechanism is common between Type Icn (and also Type Ibn) SNe. The CSM masses of SN 2021ckj and SN 2021csp are higher than that of SN 2019hgp, although all these values are within those seen in Type Ibn SNe. The early spectrum of SN 2021ckj shows narrow emission lines from C II and C III, without a clear absorption component, in contrast with that observed in SN 2021csp. The similarity of the emission components of these lines implies that the emitting regions of SNe 2021ckj and 2021csp have similar ionization states, and thus suggests that they have similar properties as the ejecta and CSM, which is also inferred from the LC modeling. Taking the difference in the strength of the absorption features into account, this heterogeneity may be attributed to viewing angle effects in otherwise common aspherical ejecta. In particular, in this scenario SN 2021ckj is observed from the polar direction, while SN 2021csp is seen from an off-axis direction. This is also supported by the fact that the late-time spectra of SNe 2021ckj and 2021csp show similar features but with different line velocities. © 2023 EDP Sciences. All rights reserved.Ítem 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, JunboWe 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.Ítem SN 2017ivv: Two years of evolution of a transitional Type II supernova(Oxford University Press, 2020-11) Gutiérrez C.P.; Pastorello A.; Jerkstrand A.; Galbany L.; Sullivan M.; Anderson J.P.; Taubenberger S.; Kuncarayakti H.; González-Gaitán S.; Wiseman P.; Inserra C.; Fraser M.; Maguire K.; Smartt S.; Müller-Bravo T.E.; Arcavi I.; Benetti S.; Bersier D.; Bose S.; Bostroem K.A.; Burke J.; Chen P.; Chen T.-W.; Della Valle M.; Dong S.; Gal-Yam A.; Gromadzki M.; Hiramatsu D.; Holoien T.W.-S.; Hosseinzadeh G.; Howell D.A.; Kankare E.; Kochanek C.S.; McCully C.; Nicholl M.; Pignata G.; Prieto J.L.; Shappee B.; Taggart K.; Tomasella L.; Valenti S.; Young D.R.We present the photometric and spectroscopic evolution of the Type II supernova (SN II) SN 2017ivv (also known as ASASSN- 17qp). Located in an extremely faint galaxy (Mr =-10.3 mag), SN 2017ivv shows an unprecedented evolution during the 2 yr of observations. At early times, the light curve shows a fast rise (~6-8 d) to a peak of Mmaxg = -17.84 mag, followed by a very rapid decline of 7.94 ± 0.48 mag per 100 d in the V band. The extensive photometric coverage at late phases shows that the radioactive tail has two slopes, one steeper than that expected from the decay of 56Co (between 100 and 350 d), and another slower (after 450 d), probably produced by an additional energy source. From the bolometric light curve, we estimated that the amount of ejected 56Ni is ~0.059 ± 0.003M⊙. The nebular spectra of SN 2017ivv show a remarkable transformation that allows the evolution to be split into three phases: (1) Ha strong phase ([removed]500 d).We find that the nebular analysis favours a binary progenitor and an asymmetric explosion. Finally, comparing the nebular spectra of SN 2017ivv to models suggests a progenitor with a zero-age main-sequence mass of 15-17M⊙. © 2020 The Author(s).