Candidate Tidal Dwarf Galaxies in Arp 305: Lessons on Dwarf Detachment and Globular Cluster Formation

TL;DR

This study uses UV and optical observations along with simulations to identify and analyze young star-forming regions and candidate tidal dwarf galaxies in the interacting galaxy pair Arp 305, providing insights into dwarf galaxy formation.

Contribution

It presents the identification of 45 young star-forming clumps, including TDG candidates, and models their evolution using hydrodynamics simulations, advancing understanding of tidal dwarf galaxy formation.

Findings

45 young star-forming clumps identified

Several candidate tidal dwarf galaxies discovered

Clumps are very young, around 6 Myr old

Abstract

To search for Tidal Dwarf Galaxies (TDGs) and to study star formation in tidal features, we are conducting a large UV imaging survey of interacting galaxies selected from the Arp (1996) Atlas using the GALEX telescope. As part of that study, we present a GALEX UV and SDSS and SARA optical study of the gas-rich interacting galaxy pair Arp 305 (NGC 4016/7). The GALEX UV data reveal much extended diffuse UV emission and star formation outside the disks. This includes a luminous star forming region between the two galaxies, and a number of such regions in tidal tails. We have identified 45 young star forming clumps in Arp 305, including several TDG candidates. By comparing the UV and optical colors to population synthesis models, we determined that the clumps are very young, with several having ages of about 6 Myr. We do not find many intermediate age clumps in spite of the fact that the last closest encounter was about 300 Myr ago. We have used a smooth particle hydrodynamics code to model the interaction and determine the fate of the star clusters and candidate TDGs.