Perceiving the equation of state of Dark Energy while living in a Cold Spot

TL;DR

This paper investigates how living in a large-scale over-density like the Cold Spot can bias our measurements of Dark Energy's equation of state, potentially causing up to a ten percent misestimation.

Contribution

It introduces a model to quantify the impact of large-scale structures on perceived Dark Energy parameters, highlighting a significant observational bias.

Findings

Large structures can alter perceived Dark Energy parameters by up to 10%

Living in a Cold Spot-like region affects cosmological measurements

The effect is significant for structures with Gpc-scale dimensions

Abstract

The Cold Spot could be an adiabatic perturbation on the surface of last scattering, in which case it is an over-density with comoving radius of the order of 1 Gpc. We assess the effect that living in a similar structure, without knowing it, has on our perception of the equation of state of Dark Energy. We find that structures of dimensions such that they could cause the Cold Spot on the CMB, affect the perceived equation of state of Dark Energy possibly up to ten percent.