Clustering of Local Group distances: publication bias or correlated measurements? VI. Extending to Virgo cluster distances

TL;DR

This paper compiles and analyzes a comprehensive set of Virgo cluster distance measurements to extend the Local Group distance framework, providing updated distance estimates and implications for black hole mass calculations.

Contribution

It introduces an extensive, updated database of Virgo cluster distances and recommends a new distance modulus based on recent measurements, extending the Local Group distance framework.

Findings

Recommended distance modulus for M87: 31.03 ± 0.14 mag

Updated black hole mass estimate: (5.9 ± 0.6) × 10^9 M_d7

Distance measurements are consistent across primary and secondary indicators

Abstract

We have established an internally consistent Local Group distance framework, using the Galactic Center, the Large Magellanic Cloud, and Messier 31 (M31) as important stepping stones. At greater distances, few distance benchmarks are available. As a consequence, M87 and/or Virgo cluster distances are often invoked as the next rung on the ladder to more distant objects such as the Fornax and Coma clusters. Therefore, we extensively mined the published literature for independently derived distance estimates to either M87 or the center of the Virgo cluster. Based on our newly compiled, comprehensive database of 213 such distances, published between 1929 and 2017 July, we recommend an outward extension to our distance framework, $(m-M)_0^{\rm M87} = 31.03 \pm 0.14$ mag ($D = 16.07 \pm 1.03$ Mpc; where the uncertainty represents the Gaussian $\sigma$ of the distribution), based on a subset of recent (post-1990) M87/Virgo cluster distance measurements. The most stable distance tracers employed here were derived from analysis of both primary and secondary distance indicators. Among the former, we preferentially rely on Cepheid period--luminosity relations and red-giant-branch terminal magnitudes; our preferred secondary distance tracers are surface brightness fluctuations. Our updated distance modulus to M87 implies a slightly reduced black hole mass of $(5.9 \pm 0.6) \times 10^9 M_\odot$ with respect to that determined by the Event Horizon Telescope collaboration.