Constraining a late time transition of G_eff using low-z galaxy survey data

This is the repository containing the Mathematica code that reproduces the figures of arXiv:2201.05846.

Abstract

It has recently been pointed out that a gravitational transition taking place at a recent redshift $z_t$, reducing the effective gravitational constant $G_{\rm eff}$ by about $10%$ for $z>z_t$, has the potential to lead to a resolution of the Hubble tension if $z_t\lesssim 0.01$. Since $H(z)^2\sim G_{\rm eff}$, such a transition would also lead to sharp change of the slope of the Hubble diagram at $z=z_t$ and a sharp decrease in the number of galaxies per redshift bin at $z_t$. Here we attempt to impose constraints on such a transition by using two robust low-z redshift survey datasets ($z<0.01$), taken from the Six-degree Field Galaxy Survey (6dFGS) as well as the 2MASS Redshift Survey (2MRS). In both surveys, we bin the data in redshift bins and focus on the number of galaxies in each bin ($\Delta N(z_i)$). We observe a peak in the distribution of galaxies near a distance of approximately 20 Mpc in both datasets. This feature could be attributed to galactic density fluctuations, to coherent peculiar velocities of galaxies or to an ultra late-time gravitational transition in the same era. In the context of the later scenario we show that this feature could have been induced by a sharp change of $G_{\rm eff}$ by $\Delta G_{\rm eff}/G_{\rm eff} \simeq 0.6$ at $z_t\simeq 0.005$. In a conservative approach we can then impose a bound on such gravitational transition as $\Delta G_{\rm eff}/G_{\rm eff} \lesssim 0.6$. We conclude that the required level of gravitational transition $\Delta G/G \simeq 0.1$ for the resolution of the Hubble tension can not be excluded by redshift survey data at $z<0.01$.

Citing the paper

If you use any of the above codes or the figures in a published work please cite the following paper:
Constraining a late time transition of G_eff using low-z galaxy survey data
George Alestas, Leandros Perivolaropoulos and Konstantinos Tanidis, arXiv:2201.05846

Any further questions/comments are welcome.

Authors List

George Alestas - g.alestas@uoi.gr
Leandros Perivolaropoulos - leandros@uoi.gr
Konstantinos Tanidis - tanidis@fzu.cz