COMPARISON OF POLYCYCLICAROMATIC HYDROCARBONEMISSION TO HOT AND COLD DUSTEMISSION IN M51, M83 AND NGC 2403

Abstract

Using Spitzer Space Telescope Herschel Space Observatory data we investigate the relationship between the 8micro metre continuum subtracted PAH emission to 24,160 and 250 micro metre m dust emission for M51, M83 and NGC 2403. We find the 8 micro metre m emission does not correlate with the 24 micro metre m emission, showing signs of PAH inhibition in star forming regions. In NGC 2403 we find the 8 micro metre m emission correlates well with the 250 micro metre m emission, and the 8/250 micro metre m surface brightness correlates well with the 3.6 micro metre m surface brightness. This indicates the 8 micro metre m PAH emission carriers are mixed in with the diffuse interstellar medium and are heated by the evolved stellar population. In M83 we find an almost linear relationship between the 8 micro metre m and 160 micro metre m emission. We find the PAHs are mixed in with the diffuse dust and the predominant heating source of the PAH emission is the UV radiation escaping from star formation. In M51 we find a complex relationship between the different dust emission components. In some areas this is similar to M83, and in other areas there is little relationship between the 8 and 160 micro metre m and 8 and 250 micro metre m dust emissions. We conclude by discussing relating PAH emission to dust mass and the implications of the relations between the different dust components when making models of dust and PAH emission in face on galaxies.

Date of Award	31 Dec 2013
Original language	English
Awarding Institution	The University of Manchester
Supervisor	Albert Zijlstra (Supervisor)