Discerning dark energy models with high redshift standard candles

作者：Andersen P^*; Hjorth J

来源：Monthly Notices of the Royal Astronomical Society, 2017, 472(2): 1413-1420.

DOI：10.1093/mnras/stx1975

• cosmological parameters
• dark energy
• large-scale structure of Universe
• cosmology: observations
• cosmology: theory

Following the success of type Ia supernovae in constraining cosmologies at lower redshift (z less than or similar to 2), effort has been spent determining if a similarly useful standardizable candle can be found at higher redshift. In this work, we determine the largest possible magnitude discrepancy between a constant dark energy Lambda CDM cosmology and a cosmology in which the equation of state w(z) of dark energy is a function of redshift for high redshift standard candles (z greater than or similar to 2). We discuss a number of popular parametrizations of w(z) with two free parameters, w(z)CDM cosmologies, including the Chevallier-Polarski-Linder and generalization thereof, nCPL, as well as the Jassal-Bagla-Padmanabhan parametrization. For each of these parametrizations, we calculate and find the extrema of Delta mu, the difference between the distance modulus of a wzCDM cosmology and a fiducial Lambda CDM cosmology as a function of redshift, given 68 per cent likelihood constraints on the parameters P = (Omega(m), (0), w(0), w(a)). The parameters are constrained using cosmic microwave background, baryon acoustic oscillations and type Ia supernovae data using CosmoMC. We find that none of the tested cosmologies can deviate more than 0.05 mag from the fiducial Lambda CDM cosmology at high redshift, implying that high redshift standard candles will not aid in discerning between the w(z)CDM cosmology and the fiducial Lambda CDM cosmology. Conversely, this implies that if high redshift standard candles are found to be in disagreement with Lambda CDM at high redshift, then this is a problem not only for Lambda CDM but for the entire family of wzCDM cosmologies.

• 出版日期2017-12