A novel method of measuring cosmological distances using broad-line regions of quasars

TL;DR

This paper discusses a new method for measuring cosmological distances using broad-line regions of quasars, which could help resolve the Hubble constant tension by providing independent distance measurements.

Contribution

It introduces a novel approach combining spectroastrometry and reverberation mapping to measure quasar distances, offering an alternative to traditional methods.

Findings

Demonstrated the feasibility of the method on 3C 273

Provided a new independent distance measurement technique

Highlighted potential to address Hubble constant tension

Abstract

The absolute distance scale measurements in cosmology have always been an important mission. In particular, in recent years, the Hubble constant tension between the measurements from early and late universe has become a new crisis for cosmology, which calls for new, independent absolute cosmological distance measurements. Recently, a result of measuring the parallax distance to 3C 273 through spectroastrometry and reverberation mapping was reported. We comment on this novel method in this News & Views paper.