Letter to the Editor

Limits on dark energy–matter interaction from the Hubble relation for two-fluid FLRW models

¹ Tuorla Observatory, 21500 Piikkiö, Finland
² Centre for Advanced Studies of the Saint-Petersburg State Technical University, 195251, Politechnicheskaya 29, St. Petersburg, Russia
³ Isaac Newton Institute of Chile, St. Petersburg Branch
⁴ Astronomical Institute of the Saint-Petersburg University, 198904 St. Petersburg, Russia

Corresponding author: P. Teerikorpi, pekkatee@astro.utu.fi

Received: 19 May 2003
Accepted: 25 June 2003

Abstract

In the standard model (, ) it is assumed that there is no convertion (energy transfer) between the two components. However, this hypothesis requires observational tests. A general approach to multicomponent FLRW models comes from a new classification (Gromov et al. [CITE]) which naturally follows from two independent model properties: 1) stationarity (or not) of equations of state of component substances and the presence (or absence) of energy transfer between these. The associated one-fluid model becomes characterized by . For the case (which for a stationary equation state of dark energy means coherent evolution and is caused by energy transfer), a general integral expression for the analogue of the Mattig equation is derived. For flat geometry, the integral reduces to a simple analytic expression. Comparison with the magnitude-redshift relation for the standard model shows that gives the same relation within 0.05 mag in the range . The observable γ gives a robust upper limit to w in the equation of state of dark energy.