Examinando por Autor "Brennan, S.J."

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    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.
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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]
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    SN 2021foa, a transitional event between a Type IIn (SN 2009ip-like) and a Type Ibn supernova
    (EDP Sciences, 2022-06-01) Reguitti, A.; Pastorello, A.; Pignata, G.; Fraser, M.; Stritzinger, M.D.; Brennan, S.J.; Cai, Y.-Z.; Elias-Rosa, N.; Fugazza, D.; Gutierrez, C.P.; Kankare, E.; Kotak, R.; Lundqvist, P.; Mazzali, P.A.; Moran, S.; Salmaso, I.; Tomasella, L.; Valerin, G.; Kuncarayakti, H.
    We present photometric and spectroscopic data of the unusual interacting supernova (SN) 2021foa. It rose to an absolute magnitude peak of Mr= 18 mag in 20 days. The initial light curve decline shows some luminosity fluctuations before a long-lasting flattening. A faint source (Mr∼ 14 mag) was detected in the weeks preceding the main event, showing a slowly rising luminosity trend. The r-band absolute light curve is very similar to those of SN 2009ip-like events, with a faint and shorter duration brightening ('Event A') followed by a much brighter peak ('Event B'). The early spectra of SN 2021foa show a blue continuum with narrow (∼400 km s1) H emission lines that, two weeks later, reveal a complex profile, with a narrow P Cygni on top of an intermediate-width (∼2700 km s1) component. At +12 days, metal lines in emission appear and Hea lines become very strong, with Hea λ5876 reaching half of the Hα luminosity, much higher than in previous SN 2009ip-like objects. We propose that SN 2021foa is a transitional event between the H-rich SN 2009ip-like SNe and the He-rich Type Ibn SNe. © A. Reguitti et al. 2022.