Reconstructing the Cosmic Equation of State from Supernova Distances

Phys. Rev. Lett. 85, 1162 – Published 7 August 2000
Tarun Deep Saini, Somak Raychaudhury, Varun Sahni, and A. A. Starobinsky


Observations of high-redshift supernovae indicate that the Universe is accelerating. Here we present a model-independent method for estimating the form of the potential V(φ) of the scalar field driving this acceleration, and the associated equation of state wφ. Our method is based on a versatile analytical form for the luminosity distance DL, optimized to fit observed distances to distant supernovae and differentiated to yield V(φ) and wφ. Our results favor wφ-1 at the present epoch, steadily increasing with redshift. A cosmological constant is consistent with our results.


  • Received 12 October 1999
  • Revised 13 March 2000
  • Published in the issue dated 7 August 2000

© 2000 The American Physical Society

Authors & Affiliations

Tarun Deep Saini1,*, Somak Raychaudhury1,†, Varun Sahni1,‡, and A. A. Starobinsky2,3,§

  • 1Inter-University Centre for Astronomy & Astrophysics, Puné 411 007, India
  • 2Landau Institute for Theoretical Physics, 117334 Moscow, Russia
  • 3MPI für Astrophysik, 86740 Garching bei München, Germany

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