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A&A 380, 6-18 (2001)
DOI: 10.1051/0004-6361:20011398
Supernovae and the nature of the dark energy
M. Goliath1, 2, R. Amanullah3, P. Astier2, A. Goobar3 and R. Pain21 Swedish Defence Research Agency (FOI), S-172 90 Stockholm, Sweden
2 Laboratoire de Physique Nucléaire et de Hautes Énergies (LPNHE), IN2P3 -CNRS, Universités Paris VI & VII, 4 place Jussieu, Tour 33 -Rez de Chaussée, 75252 Paris Cedex 05, France
e-mail: astier@in2p3.fr,rpain@in2p3.fr
3 Fysikum, Stockholm University, Box 6730, 113 85 Stockholm, Sweden
e-mail: rahman@physto.se,ariel@physto.se
(Received 2 April 2001 / Accepted 2 October 2001 )
Abstract
The use of Type Ia supernovae as calibrated standard candles
is one of the most powerful tools to study the expansion history
of the universe and thereby its energy components. While the analysis
of some ~50 supernovae at redshifts around
has
provided strong evidence for an energy component with negative
pressure, "dark energy" , more data is needed to enable
an accurate estimate of the amount and nature of this energy.
This might be accomplished by a dedicated space telescope,
the SuperNova / Acceleration Probe (2000; SNAP), which aims at
collecting a large number of supernovae with z< 2.
In this paper we assess the ability of the SNAP mission to determine
various properties of the "dark energy."
To exemplify, we expect SNAP, if operated for three years to study
Type Ia supernovae, to be able
to determine the parameters in a linear equation of state
w(z)=w0+w1 z to within a statistical uncertainty of 
for w0 and
+0.15-0.17 for w1 assuming that the universe is known
to be flat and an independent high precision
measurement of the mass
density
, is used to constrain the fit.
A further improvement can be obtained if, in addition to
the high-z events, a large number of
low-z supernovae are included in the sample.
Key words: cosmology: cosmological parameters -- cosmology: dark matter -- stars: supernovae: general -- gravitational lensing
Offprint request: M. Goliath, Martin.Goliath@foi.se
© ESO 2001