Probing Time-Varying Dark Energy with DESI: The Crucial Role of Precision Matter Density (Ω_{m0}) Measurements
Fuente:
arXiv
Guardado en:
| Autor principal: | |
|---|---|
| Formato: | Preprint |
| Publicado: |
2025
|
| Materias: | |
| Acceso en línea: | |
| Etiquetas: |
Agregar Etiqueta
Sin Etiquetas, Sea el primero en etiquetar este registro!
|
| _version_ | 1866910064007184384 |
|---|---|
| author | Lee, Seokcheon |
| author_facet | Lee, Seokcheon |
| contents | Accurate measurements of fundamental cosmological parameters, especially the Hubble constant (H_0) and present-day matter density (Ω_{m0}), are crucial for constraining dark energy (DE) evolution. We analyze the sensitivities of cosmological observables (H(z), D_L(z), E_{G}) to Ω_{m0}, w_0, and w_an under different parametrizations. Our results show observables are far more sensitive to Ω_{m0} than to DE equation of state parameters (e.g., at z \sim 0.5, H(z)'s Ω_{m0} sensitivity is \sim 0.7 vs. w_a's \sim 0.04). This hierarchy mandates high-precision Ω_{m0} measurements to accurately constrain time-varying DE. We also find DE parameter sensitivity highly depends on parametrization; the standard CPL form shows low sensitivity to w_a, but ω(z) = w_0 + w_a \ln(1+z) significantly enhances it. Our analysis of DESI DR1/DR2 data confirms these theoretical limits: standalone DESI data primarily provides only upper limits for w_a, underscoring insufficient constraining power for a definitive time-varying DE detection. While combined datasets offer tighter constraints, interpretation requires caution due to parametrization influence. We further confirm this point using simulated Supernovae MCMC data. In conclusion, improving Ω_{m0} precision and adopting optimized parametrizations are imperative for future surveys like DESI to fully probe dark energy's nature. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2505_19052 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Probing Time-Varying Dark Energy with DESI: The Crucial Role of Precision Matter Density (Ω_{m0}) Measurements Lee, Seokcheon Cosmology and Nongalactic Astrophysics Accurate measurements of fundamental cosmological parameters, especially the Hubble constant (H_0) and present-day matter density (Ω_{m0}), are crucial for constraining dark energy (DE) evolution. We analyze the sensitivities of cosmological observables (H(z), D_L(z), E_{G}) to Ω_{m0}, w_0, and w_an under different parametrizations. Our results show observables are far more sensitive to Ω_{m0} than to DE equation of state parameters (e.g., at z \sim 0.5, H(z)'s Ω_{m0} sensitivity is \sim 0.7 vs. w_a's \sim 0.04). This hierarchy mandates high-precision Ω_{m0} measurements to accurately constrain time-varying DE. We also find DE parameter sensitivity highly depends on parametrization; the standard CPL form shows low sensitivity to w_a, but ω(z) = w_0 + w_a \ln(1+z) significantly enhances it. Our analysis of DESI DR1/DR2 data confirms these theoretical limits: standalone DESI data primarily provides only upper limits for w_a, underscoring insufficient constraining power for a definitive time-varying DE detection. While combined datasets offer tighter constraints, interpretation requires caution due to parametrization influence. We further confirm this point using simulated Supernovae MCMC data. In conclusion, improving Ω_{m0} precision and adopting optimized parametrizations are imperative for future surveys like DESI to fully probe dark energy's nature. |
| title | Probing Time-Varying Dark Energy with DESI: The Crucial Role of Precision Matter Density (Ω_{m0}) Measurements |
| topic | Cosmology and Nongalactic Astrophysics |
| url | https://arxiv.org/abs/2505.19052 |