Sarah LESLIE
(Max Planck Institute for Astronomy)
The JVLA-COSMOS 3GHz Large Project (PI Smolcic) covers the entire 2 square degree COSMOS field at 3 GHz down to an rms of 2 μJy/beam - the deepest radio levels over such a large field with superb multi-wavelength coverage to-date.In this talk, I will present new results that use the 3GHz data to calculate SFRs of galaxies out to z<5, based on the z-dependent FIR-radio correlation from Delhaize et al. 2017. In recent years the existence of a main sequence of star forming galaxies (stellar mass -SFR relation) has been established well into the peak epoch of star formation. Now, using the latest multi wavelength-photometry catalog, and by stacking the 3GHz images, we are able to measure the shape and normalisation of the main sequence out to z=5 over a larger range of stellar masses than previously. The multiwavelength dataset allows us to control the small effect of AGN-contamination on SFR measurements. We see a flattening of the main-seuqnece at low-redshift, as suggested by previous studies. Our analysis also allows us to constrain the number of star-bursts galaxies that lie above the main sequence at each epoch. Combining our results with recent determinations of the stellar mass function in the COSMOS field, we also present the evolution of the cosmic star formation rate density out to z<5 using dust-unbiased radio SFRs.