A glitch in Jorrie’s Cosmo-Calculator?

[JimJCW]

Let’s summarize the situation:

(1) The glitch associated with D_now(z) discussed in Post #1 is eliminated in LightCone8 (see Post #102).

(2) The error associated with Ω’s in Jorrie’s calculator discussed in Post #109 is fixed in LightCone8 (see Post #148).

(3) The difference in calculated D_now(z) using LightCone8 and ICRAR still needs to be resolved (see Post #102). I believe I can do that, but first, I need @pbuk and @Jorrie to change the following conversion,

1 pc = 3.262 ly​

in LightCone8 to,

1 pc = 3.261563777 ly​

This will make direct comparison of results from the two calculators possible.

 

[Jorrie]

(3) The difference in calculated D_now(z) using LightCone8 and ICRAR still needs to be resolved (see Post #102). I believe I can do that, but first, I need @pbuk and @Jorrie to change the following conversion,

1 pc = 3.262 ly​

in LightCone8 to,

1 pc = 3.261563777 ly​

This will make direct comparison of results from the two calculators possible.

This could surely improve accuracy for comparison purposes, but take note that Lightcone8 does not allow $\Omega_r$ to be identically zero, but only a minimum value through setting $z_{eq} = 999999$.

(This with reference to your Post #102, where you compared calculators for $\Omega_r = 0$)

At low redshift a tiny radiation density makes negligible difference, but not so for high redshift work.

 

[JimJCW]

This could surely improve accuracy for comparison purposes, . . .

My goal is to be able to say,

Calculation results from Lightcone8 and ICRAR are consistent.​

This is true for the following quantities,

	LightCone8​	ICRAR​
z	0.02	0.02
Scale (a)	9.803921569E-01	9.803921569E-01
H(z)	6.837765717E+01	6.837765717E+01
OmegaM	3.217304253E-01	3.217304253E-01
OmegaL	6.781722253E-01	6.781722253E-01
OmegaR	9.734946123E-05	9.734946125E-05
OmegaT	1.000000000E+00	1.000000000E+00

but not for D_now and D_then:

	LightCone8	ICRAR
z	0.02	0.02
T Gyr	1.351246087E+01	1.351276116E+01
Dnow Gpc	8.808897954E-02	8.810076113E+01
Dthen Gpc	8.636174465E-02	8.637329523E+01
rho kg/m3	8.782193743E-27	8.782799071E-27

I believe changing the conversion to ‘1 pc = 3.261563777 ly’ in LightCone8 will resolve this discrepancy.
@pbuk