Testing TachyonDominated Cosmology with Type Ia Supernovae
Abstract
An open or hyperbolic FriedmannRobertsonWalker spacetime dominated by tachyonic dark matter can exhibit an ``inflected'' expansion  initially decelerating, later accelerating  similar but not identical to that of nowstandard $\Lambda$CDM models dominated by dark energy. The features of the tachyonic model can be extracted by fitting the redshiftdistance 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 $H_0=(66.6\pm1.5)~\hbox{km/s/Mpc}$ and $H_0=(69.6\pm0.4)~\hbox{km/s/Mpc}$, respectively, for the currenttime Hubble parameter, and $t_0=(8.35\pm0.68)~\hbox{Gyr}$ and $t_0=(8.15\pm0.36)~\hbox{Gyr}$, respectively, for the comovingtime age of the Universe. Tests of the model against other observations will be undertaken in subsequent works.
 Publication:

arXiv eprints
 Pub Date:
 March 2024
 DOI:
 10.48550/arXiv.2403.13859
 arXiv:
 arXiv:2403.13859
 Bibcode:
 2024arXiv240313859K
 Keywords:

 Astrophysics  Cosmology and Nongalactic Astrophysics;
 General Relativity and Quantum Cosmology
 EPrint:
 20 pages, 8 figures