The Type Ia Supernova Color-Magnitude Relation and Host Galaxy Dust: A Simple Hierarchical Bayesian Model

Abstract

Conventional Type Ia supernova (SN Ia) cosmology analyses currently use a simplistic linear regression of magnitude versus color and light curve shape, which does not model intrinsic SN Ia variations and host galaxy dust as physically distinct effects, resulting in low color-magnitude slopes. We construct a probabilistic generative model for the dusty distribution of extinguished absolute magnitudes and apparent colors as the convolution of a intrinsic SN Ia color-magnitude distribution and a host galaxy dust reddening-extinction distribution. If the intrinsic color-magnitude ($M_B$ vs. $B-V$) slope ${\beta }_{int}$ differs from the host galaxy dust law $R_B$, this convolution results in a specific curve of mean extinguished absolute magnitude vs. apparent color. The derivative of this curve smoothly transitions from ${\beta }_{int}$ in the blue tail to $R_B$ in the red tail of the apparent color distribution. The conventional linear fit approximates this effective curve near the average apparent color, resulting in an apparent slope ${\beta }_{app}$ between ${\beta }_{int}$ and $R_B$. We incorporate these effects into a hierarchical Bayesian statistical model for SN Ia light curve measurements, and analyze a dataset of SALT2 optical light curve fits of 248 nearby SN Ia at z < 0.10. The conventional linear fit obtains ${\beta }_{app}\approx 3$. Our model finds a ${\beta }_{int}=2.3\pm 0.3$ and a distinct dust law of $R_B=3.8\pm 0.3$, consistent with the average for Milky Way dust, while correcting a systematic distance bias of $\sim 0.10$ mag in the tails of the apparent color distribution. Finally, we extend our model to examine the SN Ia luminosity-host mass dependence in terms of intrinsic and dust components.

23 pages, 16 figures, minor corrections; accepted for publication in ApJ

References in corpus (21)

• Improved Cosmological Constraints from New, Old and Combined Supernova Datasets
• Spectra and Light Curves of Six Type Ia Supernovae at 0.511 < z < 1.12 and the Union2 Compilation
• Some Aspects of Measurement Error in Linear Regression of Astronomical Data
• Observational Constraints on the Nature of the Dark Energy: First Cosmological Results from the ESSENCE Supernova Survey
• Improved Dark Energy Constraints from ~100 New CfA Supernova Type Ia Light Curves
• Supernova Constraints and Systematic Uncertainties from the First 3 Years of the Supernova Legacy Survey
• Improved Distances to Type Ia Supernovae with Multicolor Light Curve Shapes: MLCS2k2
• CfA3: 185 Type Ia Supernova Light Curves from the CfA
• SNLS3: Constraints on Dark Energy Combining the Supernova Legacy Survey Three Year Data with Other Probes
• Cosmological parameters from the comparison of peculiar velocities with predictions from the 2M++ density field
• Exoplanet population inference and the abundance of Earth analogs from noisy, incomplete catalogs
• The Carnegie Supernova Project: Intrinsic Colors of Type Ia Supernovae
• Optical and Near-Infrared Observations of the Highly Reddened, Rapidly Expanding Type Ia Supernova 2006X in M100
• Anomalous extinction behaviour towards the Type Ia SN 2003cg
• Type Ia Supernova Light Curve Inference: Hierarchical Bayesian Analysis in the Near Infrared
• The Type Ia supernova 2004S, a clone of SN 2001el, and the optimal photometric bands for extinction estimation
• SN 2002cv: A Heavily Obscured Type Ia Supernova
• Distances with <4% Precision from Type Ia Supernovae in Young Star-Forming Environments
• Determining the extragalactic extinction law with SALT. II. Additional sample
• Hierarchical probabilistic inference of cosmic shear
• Unsupervised Transient Light Curve Analysis Via Hierarchical Bayesian Inference

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