Implications of the correlation between the radio continuum and far-infrared luminosities of spiral galaxies

• Published in: Monthly notices of the Royal Astronomical Society 1990-02, Vol.242 (1), p.74-78
• Main Authors: Rengarajan, T. N., Iyengar, K. V. K.
• Format: Article
• Language: English
• Subjects: Astronomy; Earth, ocean, space; Exact sciences and technology; Normal galaxies. Extragalactic objects and systems (by type); Stellar systems. Galactic and extragalactic objects and systems. The universe
• ISSN: 0035-8711; 1365-2966
• DOI: 10.1093/mnras/242.1.74

The correlation observed between the radio continuum and the far-infrared (far-IR) luminosities for spiral galaxies has been extended to lower frequency by using the 408-MHz data of Harnett. The correlation has also been studied as a function of radio spectral index between 2.8 and 6.3 em and is found to be independent of it. The tighter correlation between the radio and the far-IR luminosities as compared to those between the blue and the radio, and the blue and the far-IR, is evidence that the electrons responsible for the radio emission mostly originate in young massive stars. The dispersion observed for the far-IR radio correlation is used to set limits on the variation of several parameters like the star formation rate, the slope of the initial mass function, the relative frequency of supernovae of type I and type II, the frequency of supernovae as a function of the morphological type of the galaxy, the magnetic fields in the galaxies, and the residence time of energetic electrons.