2020/06/30 by Kara A. Ponder, K. A. Ponder, W. M. Wood‐Vasey +10
Physics and Astronomy · #Astronomy #Astrophysics #Brightness #Galaxies: Formation, Evolution, Phenomena #Galaxy #Gamma-ray bursts and supernovae #Luminosity #Physics #Population #Stellar, planetary, and galactic studies #Supernova #astro-ph.CO #astro-ph.GA
paper · pdf · doi:10.3847/1538-4357/ac2d99
54 pages, 21 Figures, 15 Tables. Accepted to the Astrophysical Journal
arxiv created 2021/10/02 · openalex publication_date 2021/12/01 · arxiv updated 2022/01/05 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/06
Abstract We analyze 143 Type Ia supernovae (SNe Ia) observed in H band (1.6–1.8 μ m) and find that SNe Ia are intrinsically brighter in H band with increasing host galaxy stellar mass. We find that SNe Ia in galaxies more massive than 10 10.43 M ⊙ are 0.13 ± 0.04 mag brighter in H than SNe Ia in less massive galaxies. The same set of SNe Ia observed at optical wavelengths, after width–color–luminosity corrections, exhibit a 0.10 ± 0.03 mag offset in the Hubble residuals. We observe an outlier population ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mo stretchy="false">∣</mml:mo> <mml:mi mathvariant="normal">Δ</mml:mi> <mml:msub> <mml:mrow> <mml:mi>H</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>max</mml:mi> </mml:mrow> </mml:msub> <mml:mo stretchy="false">∣</mml:mo> <mml:mo>></mml:mo> <mml:mn>0.5</mml:mn> </mml:math> mag) in the H band and show that removing the outlier population moves the mass threshold to 10 10.65 M ⊙ and reduces the step in H band to 0.08 ± 0.04 mag, but the equivalent optical mass step is increased to 0.13 ± 0.04 mag. We conclude that the outliers do not drive the brightness–host-mass correlation. Less massive galaxies preferentially host more higher-stretch SNe Ia, which are intrinsically brighter and bluer. It is only after correction for width–luminosity and color–luminosity relationships that SNe Ia have brighter optical Hubble residuals in more massive galaxies. Thus, finding that SNe Ia are intrinsically brighter in H in more massive galaxies is an opposite correlation to the intrinsic (pre-width–luminosity correction) optical brightness. If dust and the treatment of intrinsic color variation were the main driver of the host galaxy mass correlation, we would not expect a correlation of brighter H -band SNe Ia in more massive galaxies.