Smallest scale clumpy star formation in Stephan's Quintet revealed from UV and IR imaging

TL;DR

This study uses UV and IR imaging to identify and analyze the smallest star-forming clumps in Stephan's Quintet, revealing hierarchical star formation at scales around 120 parsecs.

Contribution

It demonstrates the effectiveness of combining UVIT and JWST data to detect and study small-scale star-forming regions in interacting galaxies.

Findings

Star forming regions are identified at ~120 pc scales.

FUV imaging guides IR detection of smaller clumps.

Small clumps likely contain PAH molecules and dust.

Abstract

The spatial distribution and physical sizes of star forming clumps at the smallest scales provide valuable information on hierarchical star formation (SF). In this context, we report the sites of ongoing SF at ~120 pc along the interacting galaxies in Stephan's Quintet (SQ) compact group using AstroSat-UVIT and JWST data. Since ultraviolet radiation is a direct tracer of recent SF, we identified star forming clumps in this compact group from the FUV imaging which we used to guide us to detect star forming regions on JWST IR images. The FUV imaging reveals star forming regions within which we detect smaller clumps from the higher spatial resolution images of JWST, likely produced by PAH molecules and dust ionised by FUV emission from young massive stars. This analysis reveals the importance of FUV imaging data in identifying star forming regions in the highest spatial resolution IR imaging available.