We analyse the 476 SN Ia host galaxies from the All-Sky Automated Survey for Supernova (ASAS-SN) Bright Supernova Catalogues to determine the observed relative Type Ia supernova (SN) rates as a function of luminosity and host galaxy properties. We find that the luminosity distribution of the SNe Ia in our sample is reasonably well described by a Schechter function with a faint-end slope {alpha}~1.5 and a knee M_~-18.0. Our specific SN Ia rates are consistent with previous results but extend to far lower host galaxy masses. We find an overall rate that scales as (M/10^10^M{sun})^{alpha}^ with {alpha}~-0.5. This shows that the specific SN Ia rate continues rising towards lower masses even in galaxies as small as log(M*/M{sun})~<7.0, where it is enhanced by a factor of ~10-20 relative to host galaxies with stellar masses ~10^10^M{sun}_. We find no strong dependence of the specific SN Ia rate on the star formation activity of the host galaxies, but additional observations are required to improve the constraints on the star formation rates.

Cone search capability for table J/MNRAS/484/3785/tablea1 (Physical host data)