Massive stars exploding in a He-rich circumstellar medium - IX. SN 2014av, and characterization of Type Ibn SNe

Pastorello, A.; Wang, X.-F.; Ciabattari, F.; Bersier, D.; Mazzali, P. A.; Gao, X.; Xu, Z.; Zhang, J.-J.; Tokuoka, S.; Benetti, S.; Cappellaro, E.; Elias-Rosa, N.; Harutyunyan, A.; Huang, F.; Miluzio, M.; Mo, J.; Ochner, P.; Tartaglia, L.; Terreran, G.; Tomasella, L.; Turatto, M.
Bibliographical reference

Monthly Notices of the Royal Astronomical Society, Volume 456, Issue 1, p.853-869

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2
2016
Number of authors
21
IAC number of authors
1
Citations
64
Refereed citations
55
Description
We present spectroscopic and photometric data of the Type Ibn supernova (SN) 2014av, discovered by the Xingming Observatory Sky Survey. Stringent pre-discovery detection limits indicate that the object was detected for the first time about 4 d after the explosion. A prompt follow-up campaign arranged by amateur astronomers allowed us to monitor the rising phase (lasting 10.6 d) and to accurately estimate the epoch of the maximum light, on 2014 April 23 (JD = 245 6771.1 ± 1.2). The absolute magnitude of the SN at the maximum light is MR = -19.76 ± 0.16. The post-peak light curve shows an initial fast decline lasting about three weeks, and is followed by a slower decline in all bands until the end of the monitoring campaign. The spectra are initially characterized by a hot continuum. Later on, the temperature declines and a number of lines become prominent mostly in emission. In particular, later spectra are dominated by strong and narrow emission features of He I typical of Type Ibn supernovae (SNe), although there is a clear signature of lines from heavier elements (in particular O I, Mg II and Ca II). A forest of relatively narrow Fe II lines is also detected showing P-Cygni profiles, with the absorption component blueshifted by about 1200 km s-1. Another spectral feature often observed in interacting SNe, a strong blue pseudo-continuum, is seen in our latest spectra of SN 2014av. We discuss in this paper the physical parameters of SN 2014av in the context of the Type Ibn SN variety.