Open Access

Fig. 5


Multiepoch VLT spectropolarimetric observations of SN 2012aw showing the total flux FI at the top, the observed polarization angle θP (we show thequantity 180 + , in degrees), and the observed percentage polarization P (we show here the traditional polarization defined as ; see, e.g., Leonard et al. 2001). The quantities θP and P are displayed with a binning of 15 Å/bin. Each epoch is color coded (see labels and Table 2). To help gauge the reality of spectropolarimetric features, in the bottom plot we show a representative uncertainty per 15Å bin for each epoch (color coded error bars in the upper left corner), taken as the mean 1σ uncertainty in the total polarization calculated from 6900 Å to 7400 Å, a region largely free of line features at all epochs. (The particular uncertainty in any given bin rises and falls with the S/N, becoming larger in the P Cygni troughs and smaller in the peaks.) We overplot the adopted interstellar polarization based on a Serkowski law (Serkowski et al. 1975; Cikota et al. 2017) derived by assuming that the intrinsic polarization is zero at the regions of the strong, consistent, depolarization seen near the flux emission peaks of Hβ, Na i D, Hα, and the Ca ii near-infrared triplet at epoch 6 (thick black line; see Sect. 4.2 for details).

Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.

Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.

Initial download of the metrics may take a while.