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

TL;DR

This paper presents detailed spectroscopic and photometric observations of SN 2014av, a Type Ibn supernova, analyzing its light curve, spectral evolution, and physical parameters to enhance understanding of this supernova class.

Contribution

It provides the first detailed characterization of SN 2014av, including early detection, light curve analysis, and spectral features, contributing new data to the study of Type Ibn supernovae.

Findings

SN 2014av reached maximum brightness on April 23, 2014.

The supernova exhibited a rapid initial decline followed by a slower decline.

Spectra showed prominent He I emission lines and signatures of heavier elements.

Abstract

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 days after the explosion. A prompt follow-up campaign arranged by amateur astronomers allowed us to monitor the rising phase (lasting 10.6 days) and to accurately estimate the epoch of the maximum light, on 2014 April 23 (JD = 2456771.1 +/- 1.2). The absolute magnitude of the SN at the maximum light is M(R) = -19.76 +/- 0.16. The post-peak light curve shows an initial fast decline lasting about 3 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 blue-shifted 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 supernova variety.