# Far-infrared - radio correlation and magnetic field strength in star-forming early-type galaxies

## TL;DR

This study finds that star-forming early-type galaxies exhibit a tight far-infrared-radio correlation similar to late-type galaxies, with magnetic fields around 12 microGauss likely amplified by turbulent dynamos.

## Contribution

It provides the first detailed analysis of the far-infrared-radio correlation and magnetic field strengths in star-forming early-type galaxies, highlighting their similarities to late-type galaxies.

## Key findings

- Far-infrared to radio flux ratio ($'q'$) is 2.35±0.05.
- Average magnetic field strength is estimated at 12 microGauss.
- Star formation rates are around 6 solar masses per year.

## Abstract

A tight far-infrared - radio correlation similar to that in star-forming late-type galaxies is also indicated in star-forming blue early-type galaxies, in which the nuclear optical-line emissions are primarily due to star-forming activities without a significant contribution from active galactic nuclei. The average value of far-infrared to 1.4 GHz radio flux-ratio commonly represented as the $'q'$ parameter is estimated to be $2.35\pm0.05$ with a scatter of 0.16 dex. The average star formation rate estimated using 1.4 GHz radio continuum is $\sim6$ M$_{\odot}$ yr$^{-1}$ in good agreement with those estimated using far-infrared and H$\alpha$ luminosities. The radio emission is detected mainly from central region which could be associated with the star-forming activities, most likely triggered by recent tidal interactions. The average thermal contribution to total radio flux is estimated to be $\sim12$ per cent. The average value of the magnetic field strengths in the star-forming early-type galaxies is estimated to be 12$^{+11}_{-4}$ $\mu$G. These magnetic fields are very likely generated via fast amplification in small-scale turbulent dynamos acting in the star-bursting regions.