Host Galaxies of Type Ia Supernovae from the Nearby Supernova Factory

TL;DR

This study combines multi-wavelength data and spectral analysis to characterize the properties of galaxies hosting Type Ia supernovae, confirming they are typical field galaxies with well-understood metallicities and star-formation rates.

Contribution

It introduces a comprehensive method integrating UV, optical, and near-infrared data with spectral fitting to accurately determine host galaxy properties for SNe Ia.

Findings

SN Ia host galaxies follow the galaxy mass-metallicity relation.

Host galaxies have star-formation rates similar to field galaxies.

GALEX UV data improves SFR and dust extinction estimates.

Abstract

We present photometric and spectroscopic observations of galaxies hosting Type Ia supernovae (SNe Ia) observed by the Nearby Supernova Factory (SNfactory). Combining GALEX UV data with optical and near infrared photometry, we employ stellar population synthesis techniques to measure SN Ia host galaxy stellar masses, star-formation rates (SFRs), and reddening due to dust. We reinforce the key role of GALEX UV data in deriving accurate estimates of galaxy SFRs and dust extinction. Optical spectra of SN Ia host galaxies are fitted simultaneously for their stellar continua and emission lines fluxes, from which we derive high precision redshifts, gas-phase metallicities, and Halpha-based SFRs. With these data we show that SN Ia host galaxies present tight agreement with the fiducial galaxy mass-metallicity relation from SDSS for stellar masses log(M_*/M_Sun)>8.5 where the relation is well-defined. The star-formation activity of SN Ia host galaxies is consistent with a sample of comparable SDSS field galaxies, though this comparison is limited by systematic uncertainties in SFR measurements. Our analysis indicates that SN Ia host galaxies are, on average, typical representatives of normal field galaxies.