Clustering of Local Group Distances: Publication Bias or Correlated Measurements? VI. Extending to Virgo Cluster Distances

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 ) M87 0 = 31.03 ± 0.14 mag (D = 16.07 ± 1.03 Mpc; where the uncertainty represents the Gaussian σ 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 ± 0.6) × 10 9 M with respect to that determined by the Event Horizon Telescope collaboration.

The Fornax3D project: Planetary nebulae catalogue and independent distance measurements to Fornax cluster galaxies

“…On the other hand, although the Tonry et al (2001) distance for NGC 1399 comes with a larger error, it is closer to the average cluster distances presented in Blakeslee et al (2010), Tully et al (2013), andde Grijs &Bono (2020) as well as our own estimate for Fornax cluster distance. It would therefore seem a more indicative distance to NGC 1399 and the barycentre of the Fornax cluster.…”

Median Statistics Estimate of the Distance to M87

“…As the galaxy M87 lies near the center of the closest galaxy cluster to us, Virgo, it is an important rung on the distance ladder and allows us to extend the ladder to more distant clusters such as Coma and Fornax. de Grijs & Bono (2019), hereafter deGB, compiled a list of 211 distance measurements to M87 obtained by 15 different distance tracers. They report a mean value of 31.03 ± 0.14 mag after reducing their data set to 24 measurements from 3 tracers which they believe to be well-calibrated and independent.…”