The Properties of Type Ia Supernova Host Galaxies from the Sloan Digital Sky Survey

TL;DR

This study analyzes the properties and environments of 87 Type Ia supernova host galaxies from SDSS Stripe 82, revealing their brightness, distribution, and preference for isolated locations near galaxy clusters.

Contribution

It provides a detailed comparison of SN Ia host galaxies with general SDSS galaxies, highlighting their brightness, isolation, and clustering tendencies, which were previously less characterized.

Findings

SN Ia hosts are brighter than typical SDSS galaxies by ~0.3 mag.

SN Ia hosts are more often found in isolated environments.

Host galaxies tend to be near massive galaxy clusters.

Abstract

We investigate the properties and environments of Type Ia Supernova (SN Ia) host galaxies in the Stripe 82 of the Sloan Digital Sky Survey-II Supernova Survey centered on the celestial equator. Host galaxies are defined as the galaxy nearest to the supernova (SN) in terms of angular distance whose velocity difference from the SN is less than 1000 km s^{-1}. Eighty seven SN Ia host galaxies are selected from the SDSS Main galaxy sample with the apparent r-band magnitude m_r < 17.77, and compared with the SDSS Main galaxies. The SN Ia rates for early and late-type galaxies are 0.81 +- 0.19 SN (100yr)^{-1} and 0.99 +- 0.21 SN (100yr)^{-1}, respectively. We find that the host galaxies have a color distribution consistent with that of the Main galaxies, regardless of their morphology. However, host galaxies are on average brighter than the Main galaxies by ~ 0.3 mag over the range of -18.3 > M_r > -21.3. But the brighter ends of their luminosity distributions are similar. The distribution of the distance to the nearest neighbor galaxy shows that SNe Ia are more likely to occur in isolated galaxies without close neighbors. We also find that the SN Ia host galaxies are preferentially located in a region close to massive galaxy clusters compared to the Main galaxies.