Examinando por Autor "Drake A.J."

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    SNhunt151: An explosive event inside a dense cocoon
    (Oxford University Press, 2018-04) Elias-Rosa N.; Benetti S.; Cappellaro E.; Pastorello A.; Terreran G.; Morales-Garoffolo A.; Howerton S.C.; Valenti S.; Kankare E.; Drake A.J.; Djorgovski S.G.; Tomasella L.; Tartaglia L.; Kangas T.; Ochner P.; Filippenko A.V.; Ciabattari F.; Geier S.l; Howell D.A.; Isern J.; Leonini S.; Pignata G.; Turatto M.
    SNhunt151 was initially classified as a supernova (SN) impostor (nonterminal outburst of a massive star). It exhibited a slow increase in luminosity, lasting about 450 d, followed by a major brightening that reaches MV ≈ -18 mag. No source is detected to MV ≳ -13 mag in archival images at the position of SNhunt151 before the slow rise. Low-to-mid-resolution optical spectra obtained during the pronounced brightening show very little evolution, being dominated at all times by multicomponent Balmer emission lines, a signature of interaction between the material ejected in the new outburst and the pre-existing circumstellar medium. We also analysed mid-infrared images from the Spitzer Space Telescope, detecting a source at the transient position in 2014 and 2015. Overall, SNhunt151 is spectroscopically a Type IIn SN, somewhat similar to SN 2009ip. However, there are also some differences, such as a slow pre-discovery rise, a relatively broad light-curve peak showing a longer rise time (~50 d), and a slower decline, along with a negligible change in the temperature around the peak (T ≤ 104 K). We suggest that SNhunt151 is the result of an outburst, or an SN explosion, within a dense circumstellar nebula, similar to those embedding some luminous blue variables like η Carinae and originating from past mass-loss events. © 2017 The Author(s).