Constraining R$_V$ Variation Using Highly Reddened Type Ia Supernovae from the Pantheon+ Sample

Rose, Benjamin; Popovic, Brodie; Scolnic, Dan; Brout, D.

doi:10.48550/arxiv.2206.09950

Cited by 3 publications

(2 citation statements)

References 44 publications

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“…Although previous works (Mandel et al 2011;Burns et al 2014) have found evidence for an anti-correlation between 𝑅 𝑉 and reddening or apparent colour, we generally do not find a strong effect of this nature (c.f. also Rose et al 2022). Whether splitting the sample into two (𝐵 −𝑉 ≤ 0.3 and 𝐵 −𝑉 > 0.3) or three (𝐵 −𝑉 ≤ 0.3, 0.3 < 𝐵 − 𝑉 ≤ 0.7, 𝐵 − 𝑉 > 0.7) bins of apparent colour, we find consistency in the mean 𝑅 𝑉 across the range of apparent colours.…”

Section: Discussionmentioning

confidence: 52%

Constraining the SN Ia host galaxy dust law distribution and mass step: hierarchical BayeSN analysis of optical and near-infrared light curves

Thorp¹,

Mandel

2022

Monthly Notices of the Royal Astronomical Society

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We use the BayeSN hierarchical probabilistic SED model to analyse the optical–NIR (BVriYJH) light curves of 86 Type Ia supernovae (SNe Ia) from the Carnegie Supernova Project to investigate the SN Ia host galaxy dust law distribution and correlations between SN Ia Hubble residuals and host mass. Our Bayesian analysis simultaneously constrains the mass step and dust RV population distribution by leveraging optical–NIR colour information. We demonstrate how a simplistic analysis where individual RV values are first estimated for each SN separately, and then the sample variance of these point estimates is computed, overestimates the RV population variance $\sigma _R^2$. This bias is exacerbated when neglecting residual intrinsic colour variation beyond that due to light curve shape. Instead, Bayesian shrinkage estimates of σR are more accurate, with fully hierarchical analysis of the light curves being ideal. For the 75 SNe with low-to-moderate reddening (peak apparent B − V ≤ 0.3), we estimate an RV distribution with population mean μR = 2.59 ± 0.14, and standard deviation σR = 0.62 ± 0.16. Splitting this subsample at the median host galaxy mass (1010.57 M⊙) yields consistent estimated RV distributions between low- and high-mass galaxies, with μR = 2.79 ± 0.18, σR = 0.42 ± 0.24, and μR = 2.35 ± 0.27, σR = 0.74 ± 0.36, respectively. When estimating distances from the full optical–NIR light curves while marginalising over various forms of the dust RV distribution, a mass step of ≳ 0.06 mag persists in the Hubble residuals at the median host mass.

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Section: Discussionmentioning

confidence: 52%

Constraining the SN Ia host galaxy dust law distribution and mass step: hierarchical BayeSN analysis of optical and near-infrared light curves

Thorp¹,

Mandel

2022

Monthly Notices of the Royal Astronomical Society

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“…Schlafly et al 2016), so logically 𝑅 𝑉 should vary between, and even within, different SNe host galaxies. This is considered in Chen et al (2022) for a sample of DES SNe Ia in redMaGiC galaxies, and Rose et al (2022) for a sample of Pantheon+ SNe Ia (Scolnic et al 2021;Brout et al 2022). Meldorf et al (2022) suggest that a correlation between host-𝑅 𝑉 and SNe Ia properties indicate that intrinsic scatter is driven by 𝑅 𝑉 .…”

Section: Introductionmentioning

confidence: 99%

Concerning colour: The effect of environment on type Ia supernova colour in the dark energy survey

Kelsey

Sullivan

Wiseman

et al. 2022

Monthly Notices of the Royal Astronomical Society

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Recent analyses have found intriguing correlations between the colour (c) of type Ia supernovae (SNe Ia) and the size of their ‘mass-step’, the relationship between SN Ia host galaxy stellar mass (Mstellar) and SN Ia Hubble residual, and suggest that the cause of this relationship is dust. Using 675 photometrically-classified SNe Ia from the Dark Energy Survey 5-year sample, we study the differences in Hubble residual for a variety of global host galaxy and local environmental properties for SN Ia subsamples split by their colour. We find a 3σ difference in the mass-step when comparing blue (c < 0) and red (c > 0) SNe. We observe the lowest r.m.s. scatter (∼0.14 mag) in the Hubble residual for blue SNe in low mass/blue environments, suggesting that this is the most homogeneous sample for cosmological analyses. By fitting for c-dependent relationships between Hubble residuals and Mstellar, approximating existing dust models, we remove the mass-step from the data and find tentative ∼2σ residual steps in rest-frame galaxy U − R colour. This indicates that dust modelling based on Mstellar may not fully explain the remaining dispersion in SN Ia luminosity. Instead, accounting for a c-dependent relationship between Hubble residuals and global U − R, results in ≤1σ residual steps in Mstellar and local U − R, suggesting that U − R provides different information about the environment of SNe Ia compared to Mstellar, and motivating the inclusion of galaxy U − R colour in SN Ia distance bias correction.

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Concerning Colour: The Effect of Environment on Type Ia Supernova Colour in the Dark Energy Survey

Kelsey,

Sullivan,

Wiseman

et al. 2022

Preprint

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Recent analyses have found intriguing correlations between the colour (𝑐) of type Ia supernovae (SNe Ia) and the size of their mass-step, the relationship between host galaxy stellar mass and Hubble residual. These analyses suggest that the underlying cause of this relationship is dust. Using a sample of 675 photometrically-classified SNe Ia from the Dark Energy Survey 5-year sample, we study the differences in Hubble residual for a variety of host and local properties for subsamples split by their colour (𝑐). We find a 3𝜎 difference for the size of the mass-step when comparing blue (𝑐 < 0) and red (𝑐 > 0) SNe. We observe the lowest r.m.s. scatter (∼ 0.14) in Hubble residual for blue SNe in low mass or blue environments, suggesting that these objects provide the most homogeneous sample for cosmological analyses. By fitting for 𝑐-dependent relationships between Hubble residuals and 𝑀 stellar , approximating existing dust models, we remove the mass-step from the data but find significant remaining steps in rest-frame 𝑈 − 𝑅, indicating that current dust modelling based on 𝑀 stellar may not fully explain the remaining dispersion in SN luminosity. The most dispersion is removed by instead accounting for a 𝑐-dependent relationship between Hubble residuals and global 𝑈 − 𝑅, resulting in ≤ 1𝜎 remaining steps in other environmental properties, suggesting that 𝑈 − 𝑅 provides different information about the environment of SNe Ia to 𝑀 stellar . This 𝑐-dependent 𝑈 − 𝑅 relation implies that 𝑈 − 𝑅 may be more closely linked to dust, motivating the future inclusion of galaxy 𝑈 − 𝑅 colour in the correction for SN distance biases.

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Constraining R$_V$ Variation Using Highly Reddened Type Ia Supernovae from the Pantheon+ Sample

Cited by 3 publications

References 44 publications

Constraining the SN Ia host galaxy dust law distribution and mass step: hierarchical BayeSN analysis of optical and near-infrared light curves

Constraining the SN Ia host galaxy dust law distribution and mass step: hierarchical BayeSN analysis of optical and near-infrared light curves

Concerning colour: The effect of environment on type Ia supernova colour in the dark energy survey

Concerning Colour: The Effect of Environment on Type Ia Supernova Colour in the Dark Energy Survey

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