Isolated dSph galaxy KKs3 in the local Hubble flow

TL;DR

This study measures the velocity of a globular cluster in the isolated dSph galaxy KKs3 and uses it with data from nearby galaxies to analyze the local Hubble flow, revealing unexpected dynamics.

Contribution

First measurement of KKs3's globular cluster velocity and its use to investigate the local Hubble flow in the nearby universe.

Findings

KKs3's globular cluster velocity is 316±7 km/s.

The local Hubble flow shows no signs of compression from the Local Void.

Nearby isolated galaxies exhibit diverse properties without void influence.

Abstract

We present the SALT spectroscopy of a globular cluster in the center of the nearby isolated dSph galaxy KKs3 situated at a distance of 2.12 Mpc. Its heliocentric radial velocity is 316+-7 km/s that corresponds to V_{LG} = 112 km/s in the Local Group (LG) reference frame. We use its distance and velocity along with the data on other 35 field galaxies in the proximity of the LG to trace the local Hubble flow. Some basic properties of the local field galaxies: their morphology, absolute magnitudes, average surface brightnesses, specific star formation rates, and hydrogen mass-to-stellar mass ratios are briefly discussed. Surprisingly, the sample of the neighboring isolated galaxies displays no signs of compression under the influence of the expanding Local Void.