Examinando por Autor "Mccully, C."

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    Forbidden hugs in pandemic times: III. Observations of the luminous red nova AT 2021biy in the nearby galaxy NGC 4631
    (EDP Sciences, 2022-11-01) Cai, Y.-Z.; Pastorello, A.; Fraser, M.; Wang, X.-F.; Filippenko, A.V.; Reguitti, A.; Patra, K.C.; Goranskij, V.P.; Barsukova, E.A.; Brink, T.G.; Elias-Rosa, N.; Stevance, H.F.; Zheng, W.; Yang, Y.; Atapin, K.E.; Benetti, S.; De Boer, T.J.L.; Bose, S.; Burke, J.; Byrne, R.; Cappellaro, E.; Chambers, K.C.; Chen, W.-L.; Emami, N.; Gao, H.; Hiramatsu, D.; Howell, D.A.; Huber, M.E.; Kankare, E.; Kelly, P.L.; Kotak, R.; Kravtsov, T.; Lander, V. Yu.; Li, Z.-T.; Lin, C.-C.; Lundqvist, P.; Magnier, E.A.; Malygin, E.A.; Maslennikova, N.A.; Matilainen, K.; Mazzali, P.A.; Mccully, C.; Mo, J.; Moran, S.; Newsome, M.; Oparin, D.V.; Padilla Gonzalez, E.; Reynolds, T.M.; Shatsky, N.I.; Smartt, S.J.; Smith, K.W.; Stritzinger, M.D.; Tatarnikov, A.M.; Terreran, G.; Uklein, R.I.; Valerin, G.; Vallely, P.J.; Vozyakova, O.V.; Wainscoat, R.; Yan, S.-Y.; Zhang, J.-J.; Zhang, T.-M.; Zheltoukhov, S.G.; Dastidar, R.; Fulton, M.; Galbany, L.; Gangopadhyay, A.; Ge, H.-W.; Gutiérrez, C.P.; Lin, H.; Misra, K.; Ou, Z.-W.; Salmaso, I.; Tartaglia, L.; Xiao, L.; Zhang, X.-H.
    We present an observational study of the luminous red nova (LRN) AT 2021biy in the nearby galaxy NGC 4631. The field of the object was routinely imaged during the pre-eruptive stage by synoptic surveys, but the transient was detected only at a few epochs from ∼231 days before maximum brightness. The LRN outburst was monitored with unprecedented cadence both photometrically and spectroscopically. AT 2021biy shows a short-duration blue peak, with a bolometric luminosity of ∼1.6×1041 erg s-1, followed by the longest plateau among LRNe to date, with a duration of 210 days. A late-time hump in the light curve was also observed, possibly produced by a shell-shell collision. AT 2021biy exhibits the typical spectral evolution of LRNe. Early-time spectra are characterised by a blue continuum and prominent H emission lines. Then, the continuum becomes redder, resembling that of a K-type star with a forest of metal absorption lines during the plateau phase. Finally, late-time spectra show a very red continuum (TBB ≈ 2050 K) with molecular features (e.g., TiO) resembling those of M-type stars. Spectropolarimetric analysis indicates that AT 2021biy has local dust properties similar to those of V838 Mon in the Milky Way Galaxy. Inspection of archival Hubble Space Telescope data taken on 2003 August 3 reveals a ∼20 M⊗ progenitor candidate with log (L/L⊗) = 5.0 dex and Teff 5900 K at solar metallicity. The above luminosity and colour match those of a luminous yellow supergiant. Most likely, this source is a close binary, with a 17-24 M⊗ primary component. © Y.-Z. Cai et al. 2022.
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    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]