2019/11/30 by Tao Yang, Aritra Banerjee, Eoin Ó Colgáin · 2 citations
Physics and Astronomy · #astro-ph.CO #astro-ph.GA #astro-ph.HE #gr-qc
paper · pdf · doi:10.1103/physrevd.102.123532
published as Phys. Rev. D 102, 123532 (2020) · v3 22 pages, 10 figures, a major revision; v4 wording improved, typos corrected, conclusions unchanged; v5 and v6 match published version
arxiv created 2020/12/23 · arxiv updated 2020/12/24
Risaliti, Lusso & collaborators have constructed a high-redshift Hubble diagram of supernovae (SNe); quasars (QSO) and gamma-ray bursts (GRB) that shows a "∼ 4 σ tension with the ΛCDM model" based on a log polynomial cosmographic expansion (Risaliti et.al 2018, Lusso et.al 2019). In this work, we demonstrate that the log polynomial expansion generically fails to recover flat ΛCDM beyond z ∼ 2, thus undermining the ∼ 4 σ tension claim. Moreover, through direct fits of both the flat ΛCDM and the log polynomial model to the SNe+QSO+GRB dataset, we confirm that the flat ΛCDM model is preferred. Ultimately, we trace the tension to the QSO data and show that a best-fit of the flat ΛCDM model to the QSO data leads to a flat ΛCDM Universe with no dark energy within 1 σ. This marks an irreconcilable tension between the Risaliti-Lusso QSOs and flat ΛCDM.