Examinando por Autor "Kotak, Rubina"

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    Monthly Notices of the Royal Astronomical Society
    (Oxford University Press, 2020-02) Clark, Peter; Maguire, Kate; Inserra, Cosimo; Prentice, Simon; Stephen, J. Smartt; Contreras, Carlos; Hossenizadeh, Griffin; Hsiao, Eric Y.; Kankare, Erkki; Kasliwal, Mansi; Nugent, Peter; Shahbandeh, Melissa; Baltay, Charles; Rabinowitz, David; Arcavi, Iair; Ashall, Chris; Burns, Christopher R.; Callis, Emma; Chen, Ting-Wan; Diamond, Tiara; Fraser, Morgan; Howell, D. Andrew; Karamehmetoglu, Emir; Kotak, Rubina; Lyman, Joseph; Morrell, Nidia; Phillips, Mark; Pignata, Giuliano; Pursiainen, Miika; Sollerman, Jesper; Stritzinger, Maximilian; Sullivan, Mark; Young, David
    This paper describes the rapidly evolving and unusual supernova LSQ13ddu, discovered by the La Silla-QUEST survey. LSQ13ddu displayed a rapid rise of just 4.8 ± 0.9 d to reach a peak brightness of −19.70 ± 0.02 mag in the LSQgr band. Early spectra of LSQ13ddu showed the presence of weak and narrow He I features arising from interaction with circumstellar material (CSM). These interaction signatures weakened quickly, with broad features consistent with those seen in stripped-envelope SNe becoming dominant around two weeks after maximum. The narrow He I velocities are consistent with the wind velocities of luminous blue variables but its spectra lack the typically seen hydrogen features. The fast and bright early light curve is inconsistent with radioactive 56Ni powering but can be explained through a combination of CSM interaction and an underlying 56Ni decay component that dominates the later time behaviour of LSQ13ddu. Based on the strength of the underlying broad features, LSQ13ddu appears deficient in He compared to standard SNe Ib. © 2019 The Author(s)
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    The Type IIn Supernova SN 2010bt: The Explosion of a Star in Outburst
    (Institute of Physics Publishing, 2018-06) Elias-Rosa, Nancy; Van Dyk, Schuyler D.; Benetti, Stefano; Cappellaro, Enrico; Smith, Nathan; Kotak, Rubina; Turatto, Massimo; Filippenko, Alexei V.; Pignata, Giuliano; Fox, Ori D.; Galbany, Lluis; González-Gaitán, Santiago; Miluzio, Matteo; Monard L.A.G.; Ergon, Mattias
    It is well known that massive stars (M > 8 M ) evolve up to the collapse of the stellar core, resulting in most cases in a supernova (SN) explosion. Their heterogeneity is related mainly to different configurations of the progenitor star at the moment of the explosion and to their immediate environments. We present photometry and spectroscopy of SN 2010bt, which was classified as a Type IIn SN from a spectrum obtained soon after discovery and was observed extensively for about 2 months. After the seasonal interruption owing to its proximity to the Sun, the SN was below the detection threshold, indicative of a rapid luminosity decline. We can identify the likely progenitor with a very luminous star (log L/L ≈ 7) through comparison of Hubble Space Telescope images of the host galaxy prior to explosion with those of the SN obtained after maximum light. Such a luminosity is not expected for a quiescent star, but rather for a massive star in an active phase. This progenitor candidate was later confirmed via images taken in 2015 (∼5 yr post-discovery), in which no bright point source was detected at the SN position. Given these results and the SN behavior, we conclude that SN 2010bt was likely a Type IIn SN and that its progenitor was a massive star that experienced an outburst shortly before the final explosion, leading to a dense H-rich circumstellar environment around the SN progenitor. © 2018. The American Astronomical Society. All rights reserved.