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

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), 24μm 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 24μm-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.