The observed infall of galaxies towards the Virgo cluster

TL;DR

This study analyzes galaxy velocities around the Virgo cluster to estimate its mass and the zero-velocity surface, accounting for observational biases and using multiple distance measurement methods.

Contribution

It provides a new estimate of the Virgo cluster's mass and zero-velocity radius using a large galaxy sample and detailed velocity-distance analysis.

Findings

Zero-velocity surface radius estimated at 5.0-7.5 Mpc.

Virgo cluster mass estimated between 2.7 and 8.9 x 10^{14} solar masses.

Results consistent with previous virial mass estimates.

Abstract

We examine the velocity field of galaxies around the Virgo cluster induced by its overdensity. A sample of 1792 galaxies with distances from the Tip of the Red Giant Branch, the Cepheid luminosity, the SNIa luminosity, the surface brightness fluctuation method, and the Tully-Fisher relation has been used to study the velocity-distance relation in the Virgocentric coordinates. Attention was paid to some observational biases affected the Hubble flow around Virgo. We estimate the radius of the zero-velocity surface for the Virgo cluster to be within (5.0 - 7.5) Mpc corresponding to (17 - 26)^\circ at the mean cluster distance of 17.0 Mpc. In the case of spherical symmetry with cosmological parameter \Omega_m=0.24 and the age of the Universe T_0= 13.7 Gyr, it yields the total mass of the Virgo cluster to be within M_T=(2.7 - 8.9) * 10^{14} M_\sun in reasonable agreement with the existing virial mass estimates for the cluster.