Correlations of gas, dust and young stellar populations in the spiral galaxy NGC 7331

TL;DR

This study investigates the physical and kinematic properties of molecular clouds, dust, and stellar populations in the spiral galaxy NGC 7331 using multiple emission lines, revealing asymmetries and correlations in the galaxy's interstellar medium.

Contribution

It provides a multi-line analysis of the ISM in NGC 7331, highlighting regional differences and correlations that enhance understanding of galaxy-scale star formation processes.

Findings

CO intensities and gas surface density peak at 40 arcsec from the center

Positive correlations between gas parameters and dust emission

Higher median physical parameters on the eastern side of the disc

Abstract

Molecular clouds (MCs) in galaxies are complex places with many phases. It is, therefore, essential to study the physics and kinematics of the MCs using multiple emission lines. We probe the physics of the molecular gas and dust in the nearby spiral galaxy NGC 7331 using multiple emission lines, i.e. carbon monoxide (CO), 24{\mu}m and far-ultraviolet (FUV) data. 14 positions were targeted across the gaseous disc of NGC 7331. We found that CO intensities, gas mass, gas surface density, and 24{\mu}m-to-FUV flux ratio (i.e. the extinction) increase up to about 40 arcsec from the centre and then start to decrease. There is a positive correlation between most of the pair of parameters studied (except FUV flux density). The beam-averaged physical parameters on the eastern side of the disc show higher median values than those on the western side. Our results indicate that the star formation activity, stellar populations and overall physical properties of the ISM are different on either side of the disc. Our study provides notable insights into the complex nature of the interstellar medium (ISM) in galaxies and has the potential to provoke future higher-resolution studies yet to come.