Cosmomc: the reduced \\chi^2
Posted: April 22 2006
Hi,
I am sorry if my question does not make sense.
The WMAP3 paper, Spergel et al. astro-ph/0603449 page 7, says: "that the reduced \chi_{\rm eff}^2 is 1.041 for the combined TT and TE data (1410 D.O.F., including TE l=24-450), quarter of the detected EE signal." So I would expect that the \chi^2 is 1.041*1410=1467.81. But I usually get the \chi^2=11266. I think I misunderstand something. What is wrong here?
I set the num_cls=3 as default. So cosmomc should include TT, TE, and EE. Is it the reason why I got a large number of \chi^2? However, I also set num_cls=3 in July 2005 version of cosmomc and WMAP1 data; in that case, I got best fit values and \chi^2 very close to those given by WMAP1 paper.
I use the \Lambda CDM model; most parameters and options are default. I am using April 2006 version.
Thanks!
Loison Hoi
21 Apr 2006
I am sorry if my question does not make sense.
The WMAP3 paper, Spergel et al. astro-ph/0603449 page 7, says: "that the reduced \chi_{\rm eff}^2 is 1.041 for the combined TT and TE data (1410 D.O.F., including TE l=24-450), quarter of the detected EE signal." So I would expect that the \chi^2 is 1.041*1410=1467.81. But I usually get the \chi^2=11266. I think I misunderstand something. What is wrong here?
I set the num_cls=3 as default. So cosmomc should include TT, TE, and EE. Is it the reason why I got a large number of \chi^2? However, I also set num_cls=3 in July 2005 version of cosmomc and WMAP1 data; in that case, I got best fit values and \chi^2 very close to those given by WMAP1 paper.
I use the \Lambda CDM model; most parameters and options are default. I am using April 2006 version.
Thanks!
Loison Hoi
21 Apr 2006