Ipac logo
Closing the Redshift Gap: Testing Type Ia Supernova Evolution Across the Cosmology Sample
Program ID 19041
Science Category Large Scale Structure of the Universe
Program Type Analysis
Category Small
Principal Investigator Matthew Siebert
PI Institution Space Telescope Science Institute / STScI
Co-Investigators
  • Rodrigo Angulo (Johns Hopkins University)
  • David Coulter (Johns Hopkins University)
  • Kyle Davis (University of California, Santa Cruz)
  • Christa DeCoursey (University of Arizona, Steward Observatory)
  • Eiichi Egami (University of Arizona, Steward Observatory)
  • Michael Engesser (Space Telescope Science Institute / STScI)
  • Ryan Foley (University of California, Santa Cruz)
  • Ori Fox (Space Telescope Science Institute / STScI)
  • Sebastian Gomez (University of Texas, Austin)
  • Massimo Griggio (Space Telescope Science Institute / STScI)
  • Zachary Lane (University of Canterbury)
  • Conor Larison (Space Telescope Science Institute / STScI)
  • Maryam Modjaz (University of Virginia)
  • Thomas Moore (Space Telescope Science Institute / STScI)
  • Justin Pierel (Space Telescope Science Institute / STScI)
  • Armin Rest (Space Telescope Science Institute / STScI)
  • Melissa Shahbandeh (Space Telescope Science Institute / STScI)
  • Koji Shukawa (Johns Hopkins University)
  • Louis-Gregory Strolger (Space Telescope Science Institute / STScI)
  • Yossef Zenati (Johns Hopkins University)
  • Qinan Qang (Massachusetts Institute of Technology)
  • Estefania Padilla-Gonzalez (Johns Hopkins University)
Abstract The Roman High Latitude Time Domain Survey (HLTDS) will revolutionize Type Ia supernova (SN Ia) cosmology with distance measurements of thousands of SNe up to z ~ 3. This experiment will enable critical constraints on the existence of an evolving dark energy equation of state (wa). While spectroscopic properties are not currently used to calibrate SN Ia distances, some important studies have found relationships between Hubble Residual and ejecta velocity indicating unaccounted SN Ia physics. These trends are expected to evolve with redshift and could thus bias the measurement of wa. We propose to investigate the HLTDS SN Ia prism sample which will observe SNe Ia near peak-brightness from z = 0.3 - 1.5. While the SN Cosmology Project Infrastructure Team will provide SN Ia spectral time series, classifications, and redshifts, it will not perform subclassification or characterize spectral features. Through stacking of spectral time series, we will measure the fraction of high-velocity (vSi II > 12, 000 km s-1) SNe Ia as a function of redshift. This sample (N > 500) will fill an important redshift gap, connecting the local population SNe Ia (z > 0.5) to those only observable with JWST (z > 1.5). Precise distances to these SNe from Roman multiband light curves will allow us to constrain systematic uncertainty related to SN Ia velocity (and other spectral variability), and its impact on tests of evolving dark energy, one of the main science drivers for Roman.