Comparison of different star forming tracers in AGN host galaxies

It is notoriously difficult to measure star formation rates in AGN host galaxies as most tracer are contaminated by the AGN emission. Nevertheless, it is important to measure the SFR to directly probe feedback from AGN. As an additional complication, different SFR tracer probe star formation on different timescales from a few to 100Myr. For CARS we are able to probe the SFR from various traces which may allow us to probe a recent decline or rise in the SFR within the last 100Myr.With the advantage of our the multi-wavelength dataset for CARS we can measure the SFR using the following tracers:

  • Ha line (SFR on 5Myr timescale) based on the MUSE optical IFU data. QSO-host deblending using QDeblend3D plus AGN-SF mixing correction based on BPT allows a clean SFR measure
  • 1.4GHz radio continuum (SFR on 20Myr timescale) based on VLA data. We obtained  L-band continuum observation in A-array and C-array VLA configuration, so we can subtract the AGN core and jet emission from the large scale continuum tracing star formation making a proper correction.
  • FIR dust continuum (SFR on <100Myr timescale) based on multi-wavelength photoemtry. We can model the overall SED from X-rays to radio wavelength and thereby estimate the FIR luminosity originate from cold dust emission as  a clean tracer for star formation.

Like the GAMA survey we may be able to recover any trend of SFR changes that could be linked to AGN properties or other characteristics of their AGN host galaxy. Thereby we will probe what the primary regulator for the star formation in those AGN host galaxies.