2016MNRAS.456..853P

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 Hei typical of Type Ibn supernovae (SNe), although there is a clear signature of lines from heavier elements (in particular Oi, Mgii and CaII). A forest of relatively narrow Feii lines is also detected showing P-Cygni profiles, with the absorption component blueshifted by about 1200 km/s. 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.