The Foundation Supernova Survey: Photospheric Velocity Correlations in Type Ia Supernovae

Journal Article · Tue Dec 28 00:00:00 EST 2021 · The Astrophysical Journal

DOI:https://doi.org/10.3847/1538-4357/ac2ee5· OSTI ID:1981235

Dettman, Kyle G. ^[1]; Jha, Saurabh W. ^[2]; Dai, Mi ^[1]; Foley, Ryan J. ^[3]; Rest, Armin ^[4]; Scolnic, Daniel M. ^[5]; Siebert, Matthew R. ^[3]; Chambers, K. C. ^[6]; Coulter, D. A. ^[3]; Huber, M. E. ^[6]; Johnson, E. ^[7]; Jones, D. O. ^[3]; Kilpatrick, C. D. ^[3]; Kirshner, R. P. ^[8]; Pan, Y. -C. ^[9]; Riess, A. G. ^[10]; Shultz, A. S. B. ^[6]

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1. Rutgers Univ., Piscataway, NJ (United States); Johns Hopkins Univ., Baltimore, MD (United States)
2. Rutgers Univ., Piscataway, NJ (United States)
3. Univ. of California, Santa Cruz, CA (United States)
4. Space Telescope Science Institute, Baltimore, MD (United States)
5. Duke Univ., Durham, NC (United States)
6. Univ. of Hawaii, Honolulu, HI (United States)
7. Johns Hopkins Univ., Baltimore, MD (United States)
8. Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States)
9. National Central Univ., Taoyuan (Taiwan)
10. Johns Hopkins Univ., Baltimore, MD (United States); Space Telescope Science Institute, Baltimore, MD (United States)

The ejecta velocities of Type Ia supernovae (SNe Ia), as measured by the Si ii λ6355 line, have been shown to correlate with other supernova properties, including color and standardized luminosity. We investigate these results using the Foundation Supernova Survey, with a spectroscopic data release presented here, and photometry analyzed with the SALT2 light-curve fitter. We find that the Foundation data do not show significant evidence for an offset in color between SNe Ia with high and normal photospheric velocities, with Δc = 0.004 ± 0.015. Our SALT2 analysis does show evidence for redder high-velocity SNe Ia in other samples, including objects from the Carnegie Supernova Project, with a combined sample yielding Δc = 0.018 ± 0.008. When split on velocity, the Foundation SNe Ia also do not show a significant difference in Hubble diagram residual, ΔHR = 0.015 ± 0.049 mag. Intriguingly, we find that SN Ia ejecta velocity information may be gleaned from photometry, particularly in redder optical bands. For high-redshift SNe Ia, these rest-frame red wavelengths will be observed by the Nancy Grace Roman Space Telescope. Our results are in line with previous work that suggests SN Ia host-galaxy stellar mass is correlated with ejecta velocity: high-velocity SNe Ia are found nearly exclusively in high-stellar-mass hosts. However, host-galaxy properties alone do not explain velocity-dependent differences in supernova colors and luminosities across samples. Measuring and understanding the connection between intrinsic explosion properties and supernova environments, across cosmic time, will be important for precision cosmology with SNe Ia.

• Research Organization: Rutgers Univ., Piscataway, NJ (United States)
• Sponsoring Organization: Gordon and Betty Moore Foundation; National Aeronautics and Space Administration (NASA); National Science Foundation (NSF); USDOE Office of Science (SC)
• Grant/Contract Number: SC0011636
• OSTI ID: 1981235
• Journal Information: The Astrophysical Journal, Journal Name: The Astrophysical Journal Journal Issue: 2 Vol. 923; ISSN 0004-637X
• Publisher: IOP Publishing
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
Type Ia supernovae
cosmological parameters
observational cosmology