The Far-Infrared Radio Correlation at low radio frequency with
  LOFAR/H-ATLAS
  The radio and far-infrared luminosities of star-forming galaxies are tightly
correlated over several orders of magnitude; this is known as the far-infrared
radio correlation (FIRC). Previous studies have shown that a host of factors
conspire to maintain a tight and linear FIRC, despite many models predicting
deviation. This discrepancy between expectations and observations is concerning
since a linear FIRC underpins the use of radio luminosity as a star-formation
rate indicator. Using LOFAR 150MHz, FIRST 1.4 GHz, and Herschel infrared
luminosities derived from the new LOFAR/H-ATLAS catalogue, we investigate
possible variation in the monochromatic (250$\mathrm{\mu m}$) FIRC at low and
high radio frequencies. We use statistical techniques to probe the FIRC for an
optically-selected sample of 4,082 emission-line classified star-forming
galaxies as a function of redshift, effective dust temperature, stellar mass,
specific star formation rate, and mid-infrared colour (an empirical proxy for
specific star formation rate). Although the average FIRC at high radio
frequency is consistent with expectations based on a standard power-law radio
spectrum, the average correlation at 150MHz is not. We see evidence for
redshift evolution of the FIRC at 150MHz, and find that the FIRC varies with
stellar mass, dust temperature and specific star formation rate, whether the
latter is probed using MAGPHYS fitting, or using mid-infrared colour as a
proxy. We can explain the variation, to within 1$\sigma$, seen in the FIRC over
mid-infrared colour by a combination of dust temperature, redshift, and stellar
mass using a Bayesian partial correlation technique.
