2024/03/19 by S. Krämer, Samuel H. Kramer, Kramer, Samuel H. +2 · 1 voice
Physics and Astronomy · #Astronomy and Astrophysical Research #Cosmology and Nongalactic Astrophysics (astro-ph.CO) #FOS: Physical sciences #Gamma-ray bursts and supernovae #General Relativity and Quantum Cosmology (gr-qc) #Stellar, planetary, and galactic studies #astro-ph.CO #gr-qc
paper · pdf · doi:10.48550/arxiv.2403.13859
openalex publication_date 2024/03/19 · arxiv published 2024/03/19 · arxiv updated 2024/03/19 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
An open or hyperbolic Friedmann-Robertson-Walker spacetime dominated by tachyonic dark matter can exhibit an ``inflected'' expansion -- initially decelerating, later accelerating -- similar but not identical to that of now-standard ΛCDM models dominated by dark energy. The features of the tachyonic model can be extracted by fitting the redshift-distance relation of the model to data obtained by treating Type Ia supernovae as standard candles. Here such a model is fitted to samples of 186 and 1048 Type Ia supernovae from the literature. The fits yield values of H0=(66.6±1.5)~\hboxkm/s/Mpc and H0=(69.6±0.4)~\hboxkm/s/Mpc, respectively, for the current-time Hubble parameter, and t0=(8.35±0.68)~\hboxGyr and t0=(8.15±0.36)~\hboxGyr, respectively, for the comoving-time age of the Universe. Tests of the model against other observations will be undertaken in subsequent works.