[astro-ph/0603647] The Hubble Constant: A Summary of the HST
Posted: February 27 2007
This HST Hubble parameter summary paper gives a lower value than the widely cited Freedman et al paper from 2001, astro-ph/0012376, which found [tex]h=0.72\pm0.08[/tex], consistent with the CMB parameter fits of the [tex]\Lambda[/tex]CDM model.
These authors find [tex]h=0.62\pm0.05[/tex]. They claim that the difference with Freedman et al is due to the "untenable" treatment of Cepheid distances by the latter. (The authors note that with the improved treatment of Cepheids, Freedman et al would get [tex]h=0.60[/tex].)
Sandage and Tammann also have a more recent paper supporting the low value of [tex]h[/tex], astro-ph/0608677.
It seems that people have not paid much attention to these results. (For example, the Freedman et al value is still commonly applied as an external prior in CMB analysis.) is there some physics reason for this? The paper appears authoritative and careful. (This of course does not guarantee correctness - and I know nothing about Cepheids.) Is there something wrong with the analysis?
These authors find [tex]h=0.62\pm0.05[/tex]. They claim that the difference with Freedman et al is due to the "untenable" treatment of Cepheid distances by the latter. (The authors note that with the improved treatment of Cepheids, Freedman et al would get [tex]h=0.60[/tex].)
Sandage and Tammann also have a more recent paper supporting the low value of [tex]h[/tex], astro-ph/0608677.
It seems that people have not paid much attention to these results. (For example, the Freedman et al value is still commonly applied as an external prior in CMB analysis.) is there some physics reason for this? The paper appears authoritative and careful. (This of course does not guarantee correctness - and I know nothing about Cepheids.) Is there something wrong with the analysis?