Notes. ^(a) MW E(B− V) in magnitudes from Schlafly & Finkbeiner (2011). If additional host galaxy extinction is present we quote the combined Galactic and host galaxy E(B− V) in magnitudes. ^(b) Heliocentric redshifts are taken from the Nasa Extragalactic Database (NED). ^(c) Days after the explosion, assuming a rise time of ~18 days (Ganeshalingam et al. 2011). The spectra were scaled to match the photometry at this phase. ^(d) Jha et al. (1999) report the extinction towards the SN as A_V = 0.94 mag. ^(e) We subtracted a light echo as found by Cappellaro et al. (2001) scaled up by a factor of two (see Spyromilio et al. 2004). ^(f) Silverman et al. (2012) found host galaxy extinction of E(B − V) = 0.18 mag. ^(g) Resolution of the three X-shooter arms UVB/VIS/NIR ^(h)Amanullah et al. (2014) determine E(B−V) = 1.37 mag with low total-to-selective extinction R_V = 1.4.

References. (1) Spyromilio et al. (2004); (2) Maguire et al. (2016); (3) Maguire et al. (2018); (4) Dhawan et al. (2018).