The nature of near-infrared emission from spiral galaxies

We present K-band spectroscopy for several re- gions of three nearby spiral galaxies, NGC 613, NGC 628 and NGC 7741. Analysis of the depth of the 2.293m CO absorption feature in these spectra reveals that some regions have deep ab- sorptions, indicative of recent star formation, while others have anomalously shallow absorptions. We interpret the latter as ev- idence for a significant but localised contribution to the 2.3 m light from hot dust with an effective temperature of 1000 K, which could have a significant effect on the K-band morpholo- gies of star-forming galaxies.