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SALT3: An Improved Type Ia Supernova Model for Measuring Cosmic Distances

Publication ,  Journal Article
Kenworthy, WD; Jones, DO; Dai, M; Kessler, R; Scolnic, D; Brout, D; Siebert, MR; Pierel, JDR; Dettman, KG; Dimitriadis, G; Foley, RJ; Jha, SW ...
August 24, 2021

A spectral-energy distribution (SED) model for Type Ia supernovae (SNe Ia) is a critical tool for measuring precise and accurate distances across a large redshift range and constraining cosmological parameters. We present an improved model framework, SALT3, which has several advantages over current models including the leading SALT2 model (SALT2.4). While SALT3 has a similar philosophy, it differs from SALT2 by having improved estimation of uncertainties, better separation of color and light-curve stretch, and a publicly available training code. We present the application of our training method on a cross-calibrated compilation of 1083 SNe with 1207 spectra. Our compilation is $2.5\times$ larger than the SALT2 training sample and has greatly reduced calibration uncertainties. The resulting trained SALT3.K21 model has an extended wavelength range $2000$-$11000$ angstroms (1800 angstroms redder) and reduced uncertainties compared to SALT2, enabling accurate use of low-$z$ $I$ and $iz$ photometric bands. Including these previously discarded bands, SALT3.K21 reduces the Hubble scatter of the low-z Foundation and CfA3 samples by 15% and 10%, respectively. To check for potential systematic uncertainties we compare distances of low ($0.01

Duke Scholars

Publication Date

August 24, 2021

Related Subject Headings

  • Astronomy & Astrophysics
  • 5109 Space sciences
  • 5107 Particle and high energy physics
  • 5101 Astronomical sciences
  • 0306 Physical Chemistry (incl. Structural)
  • 0202 Atomic, Molecular, Nuclear, Particle and Plasma Physics
  • 0201 Astronomical and Space Sciences
 

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Kenworthy, W. D., Jones, D. O., Dai, M., Kessler, R., Scolnic, D., Brout, D., … Rojas-Bravo, C. (2021). SALT3: An Improved Type Ia Supernova Model for Measuring Cosmic Distances.
Kenworthy, W. D., D. O. Jones, M. Dai, R. Kessler, D. Scolnic, D. Brout, M. R. Siebert, et al. “SALT3: An Improved Type Ia Supernova Model for Measuring Cosmic Distances,” August 24, 2021.
Kenworthy WD, Jones DO, Dai M, Kessler R, Scolnic D, Brout D, et al. SALT3: An Improved Type Ia Supernova Model for Measuring Cosmic Distances. 2021 Aug 24;
Kenworthy WD, Jones DO, Dai M, Kessler R, Scolnic D, Brout D, Siebert MR, Pierel JDR, Dettman KG, Dimitriadis G, Foley RJ, Jha SW, Pan Y-C, Riess A, Rodney S, Rojas-Bravo C. SALT3: An Improved Type Ia Supernova Model for Measuring Cosmic Distances. 2021 Aug 24;

Publication Date

August 24, 2021

Related Subject Headings

  • Astronomy & Astrophysics
  • 5109 Space sciences
  • 5107 Particle and high energy physics
  • 5101 Astronomical sciences
  • 0306 Physical Chemistry (incl. Structural)
  • 0202 Atomic, Molecular, Nuclear, Particle and Plasma Physics
  • 0201 Astronomical and Space Sciences