Free Access

Fig. 2


Obtained spectra after removing the linear continuum defined by a least-squares fit to the 0.55 − 0.85   μm wavelength range. The solid thick lines represent a polynomial fit to each spectrum, clearly showing that in the region around 0.7   μm the three spectra align on the same line, which is flat and has no absorption features.

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.