The innermost region of the NGC 1023 Group: Insight into its evolution

TL;DR

This study combines ultraviolet observations and simulations to explore the evolution of the NGC 1023 group's innermost region, revealing recent merger history and new dwarf galaxy detections.

Contribution

It provides a detailed chemo-photometric model of NGC 1023's evolution, incorporating UV data and identifying new group members.

Findings

NGC 1023's SED matches a minor merger simulation.

Two new UV-detected dwarf galaxies are identified.

Major interaction occurred 7.7 Gyr ago, final merger 1.8 Gyr ago.

Abstract

The NGC 1023 group is one of the most studied nearby groups. We want to give an insight into the evolution of its innermost region by means of ultraviolet observations and proper models. We used the FUV and NUV GALEX archival data as well as a large set of SPH simulations with chemo-photometric implementation. From the UV observations we found that several, already known, dwarf galaxies very close to NGC 1023 are also detected in UV and two more objects (with no optical counterpart) can be added to the group. Using these data we construct exhaustive models to account for their formation. We find that the whole SED of NGC 1023 and its global properties are well matched by a simulation which provides a minor merger with a companion system 5 times less massive. The strong interaction phase started 7.7 Gyr ago and the final merger 1.8 Gyr ago.