SN 2016adj light curves

We present a comprehensive data set of supernova (SN) 2016adj located within the central dust lane of Centaurus A. SN 2016adj is significantly reddened and after correcting the peak apparent B-band magnitude (m_B_=17.48+/-0.05) for Milky Way reddening and our inferred host-galaxy reddening parameters (i.e., RV^host^=5.7+/-0.7 and AV^host^=6.3+/-0.2mag), we estimated it reached a peak absolute magnitude of M_B_~-18. A detailed inspection of the optical and near-infrared (NIR) spectroscopic time series reveals a carbon-rich SN Ic and not a SN Ib/IIb as previously suggested in the literature.

The NIR spectra show prevalent carbon-monoxide formation occurring already by +41 days past B-band maximum, which is ~11 days earlier than previously reported in the literature for this object. Interestingly, around two months past maximum, the NIR spectrum of SN 2016adj begins to exhibit H features, with a +97 days medium resolution spectrum revealing both Paschen and Bracket lines with absorption minima of ~2000km/s, full-width-half-maximum emission velocities of ~1000km/s, and emission line ratios consistent with a dense emission region.