HUBBLE RESIDUALS OF NEARBY TYPE Ia SUPERNOVAE ARE CORRELATED WITH HOST GALAXY MASSES

Abstract

From Sloan Digital Sky Survey u' g' r' i' z' imaging, we estimate the stellar masses of the host galaxies of 70 low redshift SN Ia (0.015 < z < 0.08) from the hosts' absolute luminosities and mass-to-light ratios. These nearby SN were discovered largely by searches targeting luminous galaxies, and we find that their host galaxies are substantially more massive than the hosts of SN discovered by the flux-limited Supernova Legacy Survey. Testing four separate light curve fitters, we detect ∼2.5σ correlations of Hubble residuals with both host galaxy size and stellar mass, such that SN Ia occurring in physically larger, more massive hosts are ∼10% brighter after light curve correction. The Hubble residual is the deviation of the inferred distance modulus to the SN, calculated from its apparent luminosity and light curve properties, away from the expected value at the SN redshift. Marginalizing over linear trends in Hubble residuals with light curve parameters shows that the correlations cannot be attributed to a light curve-dependent calibration error. Combining 180 higher-redshift ESSENCE, SNLS, and HigherZ SN with 30 nearby SN whose host masses are less than 10 10.8 M in a cosmology fit yields 1 + w = 0.22−0.108 , while a combination where the 30 nearby SN instead have host masses greater than 10 10.8 M yields 1 + w = −0.03−0.143 . Progenitor metallicity, stellar population age, and dust extinction correlate with galaxy mass and may be responsible for these systematic effects. Host galaxy measurements will yield improved distances to SN Ia.

BAHAMAS: NEW ANALYSIS OF TYPE Ia SUPERNOVAE REVEALS INCONSISTENCIES WITH STANDARD COSMOLOGY

“…There is no appreciable difference in DM 0 between the Hard Classification Model and the Soft Classification Model. In accordance with previous results (Kelly et al 2010;Sullivan et al 2010;Campbell et al 2016), we find that SNe Ia in more massive galaxies are intrinsically brighter, with our posterior estimate of the magnitude difference being D = - M 0.055 0.022 0 . However, the size of the effect in our study is smaller than previously reported.…”

“…) host brighter SNe Ia, with their average absolute magnitude being of order ∼0.1 mag smaller than in less massive hosts (Kelly et al 2010;Sullivan et al 2010;Campbell et al 2016). This could be a reflection of dust, age, and/or metallicity in the progenitor systems (Childress et al 2013b).…”

Observational probes of cosmic acceleration

“…This breadth of host conditions provides a laboratory for the investigation of the evolution of SNe Ia as distance indicators. Recently such an effect was found and calibrated in the form of a modest, 0.03 mag dex −1 relationship between host galaxy stellar mass (a likely tracer of metallicity) and calibrated SN Ia magnitude (Kelly et al 2010;Lampeitl et al 2010;Sullivan et al 2010;see Hicken et al [2009b] for an analysis with host morphology and Hayden et al [2012] for an analysis that incorporates star formation rate in an attempt to isolate metallicity). At the level of precision enabled by current surveys, it is necessary to correct for this effect , but the uncertainty in the correction is not a limiting systematic.…”

Stellar Forensics with the Supernova‐GRB Connection

“…Furthermore, even for SN Ia, which arise from the thermonuclear explosion of a white dwarf at or near the Chandraskhar mass limit in a binary system, host galaxy studies have uncovered trends for SN Ia luminosity with host galaxy morphology (e.g., Hamuy et al 1996) and mass (e.g., Kelly et al 2010;Sullivan et al 2010), where more luminous SN Ia tend to be in more luminous and (assuming the luminosity-metallicity relationship for galaxies) metalrich galaxies, which is consistent with measured metallicity studies (Gallagher et al 2008). However, for SN Ia with their long delay times (200 Million yrs to a few Gigayears, e.g., Maoz 2010) and the associated large offsets between birth and explosion sites, it is not clear whether measuring the gas-phase metallicity (which reflects that of the currently starforming gas) at the SN position really reflects the natal metallicity of the old progenitor (Bravo & Badenes 2011).…”