https://doi.org/10.1140/epjc/s10052-017-5069-1
Regular Article - Theoretical Physics
New observational constraints on f(T) cosmology from radio quasars
1
Department of Astronomy, Beijing Normal University, Beijing, 100875, China
2
Department of Astrophysics and Cosmology, Institute of Physics, University of Silesia, Uniwersytecka 4, 40-007, Katowice, Poland
* e-mail: caoshuo@bnu.edu.cn
Received:
11
May
2017
Accepted:
13
July
2017
Published online:
28
July
2017
Using a new recently compiled milliarcsecond compact radio data set of 120 intermediate-luminosity quasars in the redshift range 
, whose statistical linear sizes show negligible dependence on redshifts and intrinsic luminosity and thus represent standard rulers in cosmology, we constrain three viable and most popular f(T) gravity models, where T is the torsion scalar in teleparallel gravity. Our analysis reveals that constraining power of the quasars data (
) is comparable to the Union2.1 SN Ia data (
) for all three f(T) models. Together with other standard ruler probes such as cosmic microwave background and baryon acoustic oscillation distance measurements, the present value of the matter density parameter 
obtained by quasars is much larger than that derived from other observations. For one of the models considered (
CDM) a small but noticeable deviation from 
CDM cosmology is present, while in the framework of 
CDM the effective equation of state may cross the phantom divide line at lower redshifts. These results indicate that intermediate-luminosity quasars could provide an effective observational probe comparable to SN Ia at much higher redshifts, and f(T) gravity is a reasonable candidate for the modified gravity theory.
© The Author(s), 2017
