EDP Sciences
Free access
Volume 443, Number 3, December I 2005
Page(s) 781 - 791
Section Cosmology (including clusters of galaxies)
DOI http://dx.doi.org/10.1051/0004-6361:20053025

A&A 443, 781-791 (2005)
DOI: 10.1051/0004-6361:20053025

SALT: a spectral adaptive light curve template for type Ia supernovae

J. Guy, P. Astier, S. Nobili, N. Regnault and R. Pain

Laboratoire de Physique Nucléaire et des Hautes Énergies, IN2P3, CNRS, Universités Paris VI et Paris VII, 4 place Jussieu, Tour 33, Rez de chaussée, 75252 Paris Cedex 05, France
    e-mail: guy@lpnhep.in2p3.fr

(Received 8 March 2005 / Accepted 23 June 2005 )

We present a new method to parameterize type Ia Supernovae (SN Ia) multi-color light curves. The method was developed in order to analyze the large number of SN Ia multi-color light curves measured in current high-redshift projects. The technique is based on empirically modeling SN Ia luminosity variations as a function of phase, wavelength, a shape parameter, and a color parameter. The model is trained with a sample of well-measured nearby SN Ia and then tested with an independent set of supernovae by building an optimal luminosity distance estimator that combines the supernova rest-frame luminosity, shape parameter, and color reconstructed with the model. The distances we measure using B- and V-band data show a dispersion around the Hubble line comparable or lower than obtained with other methods. With this model, we are able to measure distances using U- and B-band data with a dispersion of $0.16\pm0.05$ around the Hubble line.

Key words: supernovae: general -- cosmology: observations

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