The colour-lightcurve shape relation of Type Ia supernovae and the reddening law
Dec, 2007Citations per year
Abstract: (arXiv)
We present a study of the time sequence of optical colours of a large sample of nearby Type Ia supernovae (SNe Ia). We study the dependence of the colour time evolution with respect to the lightcurve shape, the stretch parameter. We fit the spectral template that minimizes the colour dispersion in SNe Ia, as measured through UBVRI photometry of near-by supernovae. A clear colour dependence upon lightcurve shape is found, with the narrower lightcurves being redder up to about one month past lightcurve maximum. We also derive an average reddening law, after correcting for lightcurve shape differences in intrinsic colour, that is well described by a Cardelli, Clayton & Mathis law with R_V=1.75 \pm 0.27 for 80 Type Ia supernovae with E(B-V) \le 0.7 mag. A subset sample including 69 SNe with modest reddening, E(B-V)<0.25 mag, yields a smaller value, R_V ~ 1, suggesting that the reddening of Type Ia supernovae may be the result of more than one process.Note:
- Submitted to Astron.Astrophys.
- STARS STATISTICS
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