A&A 464, 827-836 (2007)
Spectroscopic observations of eight supernovae at intermediate redshiftC. Balland1, 2, 3, M. Mouchet3, 4, R. Amanullah5, P. Astier1, S. Fabbro6, G. Folatelli5, G. Garavini5, A. Goobar5, D. Hardin1, M. J. Irwin7, R. G. McMahon7, A.-M. Mourão6, S. Nobili5, R. Pain1, R. Pascoal6, J. Raux1, G. Sainton1, K. Schahmaneche1, and N. A. Walton7
1 LPNHE, CNRS-IN2P3 and Universities of Paris 6 & 7, 75252 Paris Cedex 05, France
2 Univ. Paris-Sud, 91405 Orsay, France
3 APC, UMR 7164 CNRS, 11 place Marcelin Berthelot, 75231 Paris Cedex 05, France
4 LUTH, UMR 8102 CNRS, Observatoire de Paris, Section de Meudon, 92195 Meudon Cedex, France
5 Department of Physics, Stockholm University, 10691 Stockholm, Sweden
6 CENTRA-Centro M. de Astrofisica and Department of Physics, IST, Lisbon, Portugal
7 Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge, CB3 0HA, UK
(Received 12 October 2006 / Accepted 4 December 2006 )
Aims.We present spectra of six type Ia and two type II supernovae obtained in June 2002 at the William Herschel Telescope during a search for type Ia supernovae (SN Ia) at intermediate redshift.
Methods.Supernova type identification and phase determination are performed using a fitting technique based on a minimization against a series of model templates.
Results. The spectra range from z=0.033 to z=0.328, including one spectroscopically underluminous SN Ia at z=0.033. This set of spectra significantly increases the sample of well-observed type SN Ia supernovae available in the range . Together with the twelve supernovae observed by our team in 1999 in the same redshift range, they form an homogeneous sample of seventeen type Ia supernovae with comparable signal-to-noise ratio and regular phase sampling in a still largely unexplored region of the redshift space.
Key words: cosmology: observations -- stars: supernovae: general -- cosmology: distance scale
© ESO 2007