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Breaking the color-reddening degeneracy in type Ia supernovae

Sasdelli, M and Ishida, EEO and Hillebrandt, W and Ashall, C and Mazzali, PA and Prentice, SJ (2016) Breaking the color-reddening degeneracy in type Ia supernovae. Monthly Notices of the Royal Astronomical Society. ISSN 0035-8711

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Abstract

A new method to study the intrinsic color and luminosity of type Ia supernovae (SNe Ia) is presented. A metric space built using principal component analysis (PCA) on spectral series SNe Ia between -12.5 and +17.5 days from B maximum is used as a set of predictors. This metric space is built to be insensitive to reddening. Hence, it does not predict the part of color excess due to dust-extinction. At the same time, the rich variability of SN Ia spectra is a good predictor of a large fraction of the intrinsic color variability. Such metric space is a good predictor of the epoch when the maximum in the B-V color curve is reached. Multivariate Partial Least Square (PLS) regression predicts the intrinsic B band light-curve and the intrinsic B-V color curve up to a month after maximum. This allows to study the relation between the light curves of SNe Ia and their spectra. The total-to-selective extinction ratio RV in the host-galaxy of SNe Ia is found, on average, to be consistent with typical Milky-Way values. This analysis shows the importance of collecting spectra to study SNe Ia, even with large sample publicly available. Future automated surveys as LSST will provide a large number of light curves. The analysis shows that observing accompaning spectra for a significative number of SNe will be important even in the case of "normal" SNe Ia.

Item Type: Article
Additional Information: This is a pre-copyedited, author-produced PDF of an article accepted for publication in Monthly Notices of the Royal Astronomical Society following peer review. The version of record is available online at: http://dx.doi.org/10.1093/mnras/stw900
Uncontrolled Keywords: astro-ph.SR; astro-ph.SR; astro-ph.CO; astro-ph.GA
Subjects: Q Science > QB Astronomy
Divisions: Astrophysics Research Institute
Publisher: Oxford University Press
Related URLs:
Date Deposited: 21 Apr 2016 12:48
Last Modified: 19 May 2016 12:35
URI: http://researchonline.ljmu.ac.uk/id/eprint/3498

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