On the kinematics of the Local cosmic void

TL;DR

This study analyzes the peculiar velocity field around the Local Void using a large galaxy sample, revealing an outflow velocity of about 300 km/s and characterizing the void's galaxy population as less luminous and later-type.

Contribution

It provides a comprehensive analysis of galaxy velocities and properties around the Local Void using diverse distance measurement methods, offering new insights into void dynamics.

Findings

Outflow velocity of ~300 km/s around the void

Galaxies within the void are less luminous and later-type

Intra-void galaxy density is about 1/5 of external density

Abstract

We collected the existing data on the distances and radial velocities of galaxies around the Local Void in the Aquila/Hercules to examine the peculiar velocity field induced by its underdensity. A sample of 1056 galaxies with distances measured 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 for this purpose. The amplitude of outflow is found to be ~300 km/s. The galaxies located within the void produce the mean intra-void number density about 1/5 of the mean external number density of galaxies. The void's population has a lower luminosity and a later morphological type with the medians: M_B = -15.7^m and T = 8 (Sdm), respectively.