SALT2: using distant supernovae to improve the use of Type Ia supernovae as distance indicators

J. Guy (1) , P. Astier (1) , S. Baumont (1) , D. Hardin (1) , R. Pain (1) , N. Regnault (1) , S. Basa (2) , R.G. Carlberg , A. Conley , S. Fabbro , D. Fouchez (3) , I.M. Hook , D.A. Howell , K. Perrett , C.J. Pritchet , J. Rich (4) , M. Sullivan , P. Antilogus (1) , E. Aubourg (4) , G. Bazin (4) , J. Bronder , M. Filiol , N. Palanque-Delabrouille (4) , P. Ripoche (3) , V. Ruhlmann-Kleider (4)

1 LPNHE - Laboratoire de Physique Nucléaire et de Hautes Énergies
2 LAM - Laboratoire d'Astrophysique de Marseille
3 CPPM - Centre de Physique des Particules de Marseille
4 DAPNIA - Département d'Astrophysique, de physique des Particules, de physique Nucléaire et de l'Instrumentation Associée

We present an empirical model of Type Ia supernovae spectro-photometric evolution with time. The model is built using a large data set including light-curves and spectra of both nearby and distant supernovae, the latter being observed by the SNLS collaboration. We derive the average spectral sequence of Type Ia supernovae and their main variability components including a color variation law. The model allows us to measure distance moduli in the spectral range 2500-8000 A with calculable uncertainties, including those arising from variability of spectral features. Thanks to the use of high-redshift SNe to model the rest-frame UV spectral energy distribution, we are able to derive improved distance estimates for SNe Ia in the redshift range 0.8

Mots clés: supernovae: general; cosmology: observations

Domaines: Cosmologie et astrophysique extra-galactique [astro-ph.CO]; Astrophysique [astro-ph]

J. Guy, P. Astier, S. Baumont, D. Hardin, R. Pain, et al.. SALT2: using distant supernovae to improve the use of Type Ia supernovae as distance indicators. Astronomy and Astrophysics - A&A, 2007, 466, pp.11-21. ⟨10.1051/0004-6361:20066930⟩. ⟨in2p3-00127896⟩