On problems with cosmography in cosmic dark ages
- 발행기관 ELSEVIER
- 발행년도 2021
- 총서유형 Journal
- 본문언어 영어
초록/요약 도움말
Quasars show considerable promise as standard candles in a high-redshift window beyond Type Ia supernovae. Recently, Risaliti, Lusso & collaborators [1-3] have succeeded in producing a high redshift Hubble diagram (z less than or similar to 7) that supports a trend whereby the Hubble diagram of quasars is well reproduced by the standard flat Lambda CDM model up to z similar to 1.5 - 2, but strong deviations emerge at higher redshifts. This conclusion hinges upon a log polynomial expansion for the luminosity distance. In this note, we demonstrate that this expansion (or improvements thereof) typically can only be trusted up to z similar to 1.5 - 2. As a result, a breakdown in the validity of the expansion may be misinterpreted as a (phantom) deviation from flat Lambda CDM. We further illustrate the problem through mock data examples. (C) 2021 The Author(s). Published by Elsevier B.V.
more