https://doi.org/10.1140/epjc/s10052-020-7770-8
Regular Article - Theoretical Physics
Growth index of matter perturbations in the light of Dark Energy Survey
1
Research Center for Astronomy and Applied Mathematics, Academy of Athens, Soranou Efesiou 4, 11527, Athens, Greece
2
National Observatory of Athens, V. Paulou and I. Metaxa, 15236, Penteli, Greece
3
Department of Physics, National and Kapodistrian University of Athens, Zografou Campus GR 157 73, Athens, Greece
* e-mail: fotis-anagnostopoulos@hotmail.com
Received:
9
December
2019
Accepted:
22
February
2020
Published online:
6
March
2020
We study how the cosmological constraints from growth data are improved by including the measurements of bias from Dark Energy Survey (DES). In particular, we utilize the biasing properties of the DES Luminous Red Galaxies (LRGs) and the growth data provided by the various galaxy surveys in order to constrain the growth index (
) of the linear matter perturbations. Considering a constant growth index we can put tight constraints, up to 
accuracy, on . Specifically, using the priors of the Dark Energy Survey and implementing a joint likelihood procedure between theoretical expectations and data we find that the best fit value is in between 
and 
. On the other hand utilizing the Planck priors we obtain 
and 
. This shows a small but non-zero deviation from General Relativity (
), nevertheless the confidence level is in the range 
. Moreover, we find that the estimated mass of the dark-matter halo in which LRGs survive lies in the interval 
and 
, for the different bias models. Finally, allowing to evolve with redshift [Taylor expansion: 
] we find that the 
parameter solution space accommodates the GR prediction at 
levels.
© The Author(s), 2020
